Dominions 3: The Awakening/Nations/Oceania, Triton Kings

For ages the oceans have been dominated by the tritons of Oceana. But recently other races have been stirring in the depths and the Triton Kings muster their forces to meet the new threat. Oceana is a nation of both tritons and mermen. Tritons are unable to leave the sea, but mermen can shed their tails and walk on dry land. Both races have mages, but only the mermages can leave the sea, although their magic power is reduced when they do. The legendary Bishop Fish are powerful priests who lead the sacred Triton Knights mounted on magical Hippocampi steeds. The Early Age of Oceania is still under control of the Triton Kings.

Overview
EA Oceana hasn't gotten much love in the game forums, even though some consider it the strongest under water nation. If gem-gens are allowed, it constitutes the poster-boy for clamming and fetish farms. Without gem-gens, it is much trickier to play, as it has a tough time mid-game "breaking out" of the sea and it is easy to lose focus on setting up a strong end-game. For those wanting a challenge (or perhaps playing against opponents significantly less experienced) this does provide an opportunity for some fun or to play a handicap match.
 * Underwater nation.
 * Powerful aquatic troops and commanders, mediocre amphibious troops and commanders.
 * Expensive cap-only thug-able Triton King magi attract free Hippocampi units.
 * Powerful aquatic water magi, also with strong nature magic and splashes of air, earth and fire.
 * Amphibious magi are less powerful when on dry land.
 * Diverse magic, but it's hard to boost A/E/F without help from the pretender.
 * Powerful but expensive sacred non-cap aquatic Knights and thug-able commanders.
 * Some commander types come equipped with magic weapons, Hippocampi mounts have magical gore attack.
 * Powerful non-cap aquatic H3 Bishop Fish priests.
 * Easy access to gem-generator clams and fever fetish.
 * On land, using indies and summons is likely key to a successful strategy.

National Features
One of the downsides of Oceana is their units and commanders are only available in underwater provinces with a fort. On dry land only indie troops and commanders are available to hire, with the exception of Turtle Warriors and Turtle Chiefs available inside coastal forts.

Units

 * Oceaniac Triton: Gold 10, Resources 1
 * HP:15 Sz:2 Att:11 Def:10 Str:12 Prot:1 Prec:10	MR:12 Mor:11 Enc:3 Move:1 AP:20
 * Underwater-only chaff trooper with a spear. Look closely, this is not the same unit as the indy tritons anyone can recruit. This guy has 50% more hp, 20% more strength and 1 more MR plus higher attack and morale. That’s a pretty decent increase for a chaff unit at the same price. With the right buffs these guys start looking like real good chaff.


 * Oceanic Soldier: Gold 10, Resources 20
 * HP:15 Sz:2 Att:11 Def:12 Str:12 Prot:15 Prec:10 MR:12 Mor:11 Enc:7 Move:1 AP:16
 * Basically a heavily armed and armored version of the Oceaniac Triton. Wields trident and shield. It happens to be your slowest unit.


 * Amber Clan Guard: Gold 12, Resources 34
 * HP:16 Sz:2 Att:12 Def:12 Str:13 Prot:16 Prec:10 MR:12 Mor:12 Enc:7 Move:1 AP:18
 * Not much of an improvement over the Oceaniac Soldier, but substantially higher resource cost. Wields trident and shield.


 * Merman: Gold 10, Resources 1
 * HP:10 Sz:2 Att:10 Def:10 Str:10 Prot:1 Prec:10 MR:12 Mor:10 Enc:3 Move:1 AP:22
 * Amphibious unarmored chaff that entangles its target for its first attack. Wields spear and net, which tends to nicely blunt the first enemy charge. However, they then die quickly...


 * Turtle Warrior: Gold 11, Resources 9
 * HP:10 Sz:2 Att:10 Def:11 Str:10 Prot:8 Prec:10 MR:12 Mor:11 Enc:5 Move:1 AP:20
 * Amphibious medium shield troops. Wields spear, javelin and a shield. Use these in your amphibious armies if you expect to go up against lots of archers. Likely a solid arm of any amphibious raiding force, Turtle Warriors set to Fire Closest can be synergized with Wave Warriors.


 * Wave Warrior: Gold 13, Resources 19
 * HP:10 Sz:2 Att:11 Def:10 Str:10 Prot:15 Prec:10 MR:12 Mor:12 Enc:6 Move:1 AP:19
 * Amphibious heavy trooper. Wields a 2-handed trident. Higher protection and damage output for a corresponding raise in production cost compared to Turtle Warrior. Not many complaints. The biggest down-side is the lack of shield, which makes them vulnerable to arrow fire on land. They should have at least a light screen of troops with shields in front to protect from archers. To prepare for amphibious operations, you should generally buy as many of them as resources will permit, every turn.


 * Knight of the Deep: Gold 85, Resources 25
 * HP:16 Sz:3 Att:12 Def:17 Str:13 Prot:17 Prec:10 MR:14 Mor:15 Enc:4 Move:1 AP:30
 * Underwater-only sacred cavalry with Recuperation! Wields spear, lance, shield and a magical alicorn attack! These guys rock, but are quite expensive. In melee they are excellent. Just about any minor bless makes their already awesome stats even better. That said, their spear is disappointing and they are just as vulnerable to magma, frost and lightning as the next guy, so buff them properly vs enemy magic.


 * Hippocampus: Gold 0(special), Resources n/a
 * HP:25 Sz:2 Att:10 Def:10 Str:15 Prot:3 Prec:5 MR:13 Mor:13 Enc:2 Move:1 AP:30
 * Underwater-only "free" animal "summons" with a heavy-hitting magical weapon. Similar to Pangaea's Pans and Maenads, your Triton Kings are hard-coded to automatically randomly attract a single Hippocampi each turn (maybe 10% chance per turn?).

Commanders

 * Merman Scout: Gold 25, Resources 3, Leadership 0
 * Amphibious scout with a magic spear and net. Map-move of one. Otherwise functions like any indy scout. While on dry land it gains a feet slot.


 * Oceanian Captain: Gold 30, Resources 20, Leadership 40
 * Aquatic commander version of the Oceanic Soldier. Armed with a magic trident and shield, no feet slot.


 * Turtle Chief: Gold 40, Resources 10, Leadership 40
 * Amphibious commander version of the Turtle Warrior. Armed with a normal spear, net and shield. While on dry land they gain a feet slot.


 * Wave Lord: Gold 45, Resources 19, Leadership 80
 * Amphibious commander version of the Wave Warrior. Armed with a magic trident. While on dry land they gain a feet slot.


 * Triton Prince: Gold 125, Resources 25, Leadership 80
 * Aquatic commander version of the Knight of the Deeps. Armed with a normal lance, spear and shield and a magical gore attack. These sacred commanders can be summoned at any underwater fortress containing a temple. Similar to the KotD, these guys make excellent underwater thugs with any minor bless. Their Recuperation ability means they stay in good health, even after many battles. With an Amulet of the Fish (Const-4 A1W1), they can go on land as well.


 * Amber Clan Priest: Gold 45, Resources 2, Leadership 10
 * Aquatic H1 sacred priest. Armed with a mace, no feet slot. Has superior HP and MR compared to indy versions.


 * Merman Priest: Gold 65, Resources 1, Leadership 10
 * Amphibious H1 priest. Armed with a magical staff. Has superior MR, but otherwise similar to normal indy priests. While on dry land they gain a feet slot.
 * One interesting thing about this guy is his being sacred with a magic staff. He can self-buff if you've taken a bless. Pair him up with a mage who can cast Iron Warriors to gain some higher protection. Not that he is going to dominate the battlefield or anything, but this combo may be an inexpensive spammable anti-ethereal-counter that can push friendly dominion into enemy territory.


 * Bishop Fish: Gold 120, Resources 1, Leadership 40
 * Aquatic H3 priest with Darkvision, no feet slot. Has superior HP and MR, but the downside is Old Age and all other stats are sub-par. With a few boosters, your Amber Clan Mages might be able to furnish them with Elixir's of Life (Const-6 N2F2), otherwise your Bishop Fish's career is likely to be a disease-ridden short-lived one. They have excellent preacher skills for keeping positive candles in your border provinces, and they offer the possibility for high-level battlefield holy-magic spam.


 * Amber Clan Mage: Gold 160, Resources 1, Leadership 45, Research 6
 * Aquatic F1W2N1 mage. As with Oceania's soldiers, these triton magi display higher HP, fighting abilities and superior MR, no feet slot. As the cheapest mage on the roster, the high leadership skill and decent research comes as a nice bonus. Their combination of fire and water magic opens up some interesting possibilities, like Geyser at Alt-1, Manifest Vitriol at Alt-6 or Fever Fetish farms.
 * Give them an Amulet of the Fish to get them on land, and a Water Bracelet or Fire Skull or allow them join a Communion (see the appropriate section below). Now you're casting acid and fire evocations.


 * Mermage: Gold 175, Resources 1, Leadership 10, Research 6
 * Amphibious W2N1?(A/W/E/N 100%) mage. Armed with a magic staff, they possess excellent MR and Defense skill. While on dry land they lose 1 point of water magic, but they gain a feet slot. This isn't as bad as it sounds: give each one a Water Bracelet (you've got the gems) and every one can still cast Quickness, Desiccation, Cold Blast, Winter Ward, etc. while on land. All of them know Eagle Eyes, Barkskin, Protection regardless. With a Thistle Mace, they additionally learn Storm of Thorns, Wooden Warriors, Sleep Cloud, Berserkers which are all useful. Their random picks offer further magic diversity:


 * W2N1A1 - On land, he can cast Aim, Mirror Image, Air Shield, Resist Lightning, Orb Lightning. If you can summon a Storm (script a Fairy Queen or use Staff of Storms) he can cast Summon Storm Power to boost himself to A2 and gain Mistform, Lightning Bolt, Shockwave, Wind Guide...
 * W2N1E1 - On land, give him a pair of Earth Boots. Now he can cast Summon Earth Power and thereafter Fire Ward, Iron Warriors, Earth Meld, Blade Wind, Rust Mist, Curse of Stones, Legions of Steel, Strength of Giants...
 * W3N1 - On land with his Water Bracelet he can cast Bonemelter, Falling Frost, Curse of the Dessert, Sailors Death...
 * W2N2 - His Thistle Mace allows him to additionally cast Charm, Polymorph, Foul Vapours, Stream of Life, Touch of Madness...
 * Overall not bad land combat magic for your bread-and-butter.


 * Triton King: Gold 300, Resources 5, Leadership 120, Research 7
 * Aquatic and Capital-only sacred W4?(A/E/N 100% + A/W/E/N 10%) mage. Armed with a trident, no feet slot. While the random magic picks are quite useful, the chances of seeing a A2W4 or E2W4 are very small, so you shouldn't build a strategy around those. A third of these randoms are made for clamming. Their high hp, excellent combat stats and self buffing ability makes them by very definition a thug. In spite of their high purchase cost, they in fact require no more maintenance than the other two mage types (10 gold/turn). Each Triton King has a small (~10%) chance of automatically attracting a "free" Hippocampus unit each turn. Thus large groups of Triton Kings tend to amass large swarms of Hippocampi followers that eat up a lot of maintenance costs. They only way to prevent this is to leave the sea using Amulet of the Fish or the Transformation (Alt-7 N3) spell.
 * For combat magic, they are surprisingly restricted to almost the exact same spell sets as the Mermage (W4A1 Triton Kings can additionally cast Freezing Mist), albeit with more staying power. Their big addition is to be able to enable battlefield-wide magic like Grip of Winter, Warriors of Niefelheim and Quagmire. They can be effective both leading a Communion or acting as Communion slaves (see appropriate section below).

Heroes
None.

Starting Sites

 * Palace of Pearls:Enables recruitment of Triton King. Produces 4W, 2N gems/turn.

National Spells
None

National Summons
None. (See Hippocampus in the unit section)

General
Basically EA Oceania is immune to early game rush attacks from most land nations (beware of death-nations!) and the enemy has a lot harder time destroying your economy through raiding. You can't be too smug about this. While there are few spells and items to allow aquatic creatures to go on land, there are plenty of ways for land units to get into the water. With only some medium level magic necessary, certain land nations might look to invade you. If you become too big of a threat, there is a global that allows everyone into the water.

Thus it makes sense that Oceania has a hard time getting out of the water: if Hippocampi-riders were amphibious, EA Oceania would likely dominate the mid-game, since they could safely build up a powerful sacred force to then attack their neighbors.

Design a scales-monster pretender. Dominate the oceans, find a lot of gems, crank out amphibious troops, build item-boosters to be able to leverage your national magic. The ice/nature spells are pretty good if you use enough mages. Get a few gem-gen globals up (Maelstrom, Mother Oak). Bootstrap yourself into a couple of new paths (Air, Death and Astral, summon Faery Queens, Lamia Queens, Specters, Mound Fiends, Demi-liches, Golems, etc), and use your economy to beat down the other nations. Finish endgame using Tartarans and Wish.

In a nutshell, the following strategy works with minor modifications (In MP you need to adept to what your neighbors are doing):
 * Step 1: Dominate the seas to gain safe territory and site-search to grab ALL available sites. Unless the map is cradle or full of sea squares there are likely to be at most one other sea nation. IMO Oceania has an edge vs either of the other two EA sea nations. So dominating the seas should not be too challenging.
 * Step 2: Cast Maelstrom, Mother Oak. You should be ahead in both gems and gold even before the spell as the land nations busy themselves fighting each other. Forge boosters for your mages. If gem-gens are allowed, seriously get into clams and fetish farms.
 * Step 3: Build up large army of amphibious units and summoned creatures. With Maelstrom and your gem production you should have lots of options to gather a large effective army.
 * Step 4: Land. If you can get them there, your sacred commanders are quite tough on land too. Later in the game you might have to shift focus. You do have advantages in the water. Structures, PD, etc. and you might need to shift to a defensive strategy to hold the waters while working on alternate methods of escape (such as research).
 * Step 5: Diversify. Use land-based summoning to take advantage of all the different summons available, to keep your opponents off-balance to develop counters. Bootstrap strongly into astral and death.
 * Late Game: Just go for standard late-game magic and SCs...Tartarians, Abominations, the Water Queens, Wish. Conjuration 8 and 9, Alteration 9 essentially. You should have a clam factory up and running to supply gems for summons. Use indies or mermen for gate-bashing. Forging and summons gives you the mage support you need on the land, but those SCs are pretty tough without any help.

Opening
Your Knights of the Deep, even with only a minor bless, are practically unstoppable underwater. Half a dozen medium-blessed Hippocampi cavalry can annihilate most independent provinces without any of them ever taking an affliction, let alone losing a rider. This includes the sea-trolls, the amber-clan guards, the krackens, the leviathans, the dragon-turtles and everything else you might or might not encounter, independent-wise. If one of them do, Recuperation heals the affliction, which easily results in a veteran force of 3 star healthy units. R'lyeh and Atlantis won't even look at you funny, they're too busy outfitting the cave-fortresses they have to live in now because you're out there and only getting closer. On land you would be vulnerable to AOE spells, but underwater...what can be done? Not a lot (magma, Water Strike and orb lightning). A few dozen KotD will go through many times their number of the enemy's best troops underwater as if they were not there. I've seen 12 lvl 4+ water mages, 200+ sharks, supported by a 100+ army hit 40 Hippocampi-cavalry with dozens of water strikes/sleep clouds/geysers. It did not stop them.

Your Triton Soldiers are no slouchers either. As has already been pointed out, they are superior to indy tritons, so even 1-on-2 they should perform very well. But they become much better once you have researched Haste (ench-4) and Wooden Warriors (alt-5).

Amber Clan Mages are good early-support magi if you get rushed, since they get Geyser at evoc-1. Triton King and Mermage don't get a ranged damage spell till evoc-4. That said, you want the random picks on both those mage types for other spells and forging, so at some point switch over to TK/MM. Triton King also gets you free Hippocampi, which are arguably most useful in the early game. Beware large masses of Hippocampi eating up lots of gold for maintenance!

Grab a few nice-looking land provinces from indies if you can in the beginning...while your land troops aren't much threat to your neighbors, it's a safe bet that they will leave you a few provinces to ensure they don't have to deal with being raided. Just a good way to leverage a bit more territory. Don't go crazy topside though, the more land you have the more worthwhile it becomes to attack you, since the reward goes up while the threat of retaliation remains relatively flat.

Here's the catch: if you are exclusively mustering Knights of the Deep for your water expansion, you won't be able to take any opportunistic land provinces at all. It will likely take many turns to build up a strong enough force of Wave Warriors. So you will likely need to use a force of Turtle Warriors to catch enemy arrows flanked by Mermen chaff. Casualties will be high. It would be a good idea to prophetize a Turtle Chief for the Sermon of Courage cast. Otherwise you will be relying on the shaky morale of your weakest troops.

Site Searching
The second prong of your initial expansion rests on your underwater nature mages. The reason is because the N1 magic site Kelp Fortress is very common. How this should play out is your troops clear the seas while your first several Amber Clan Mages follow behind site searching. Unless you’re unlucky you’ll never have to build a castle, just plop a temple in the kelp fortresses you get, and you have a new source of sacred cavalry, which should be a few in the first year. This gives you a circular feedback: money savings from not building forts get pumped into summoning troops in your free fort giving you an even faster expansion. Even better, you can start dedicating some forts to land expansion the others for sea expansion.

Here is a list of the maximum levels of magic needed to search sea provinces: F1/A3/W3/E3/S3/N2/D2/H1. No underwater sites requiring higher magic exist. There are no Blood sites underwater. There is only 1 unique D2 underwater site (Dying Ground of the Whales), so D1 will mostly suffice. Any site that can be found in 'seas' can also be found in 'deepseas'.

Oceania also can easily cast Voice of Tiamat (conj-4) for remote site searching underwater, although this only finds F/A/W/E. This technically frees up your pretender and one N2 mage to cover the remaining S/N/D paths and you will still be able to discover all underwater sites.

Breakout
it is well known that Oceanic nations do well with very strong dominion and temples everywhere, since it is hard for enemies to go into the water to destroy those temples. This makes shore assaults feasible using pretenders and prophets, since you will likely be attacking into friendly dominion.

In wartime, raid enemy coastal provinces with temples to destroy them. Find a weak province, take it, hold it, then use it as a base for further land conquest. Use spells like murdering winter against large invading armies.

Use plain trident heavy infantry initially, mixed with turtle warriors and other amphibious fodder. The merfolk are weak, but you have an untouchable set of underwater provinces from which to recruit and afford 100s of the little buggers. The plan is to slowly waste away your opponent by raiding his lands till your economy eclipses his, allowing you to leverage your plentiful but weak troops. Also, there is the Water Strike spell that does strong damage to a single target. Even your weakened mermages can cast that. Create hordes of Triton Kings and make use of water bracelets and fish amulets so as to assist your armies on land by casting falling frost and desiccation AoE spells. Once you have a land base, grab archers and heavy infantry. High priority should be coastal provinces with longbowmen or crossbowmen, fortified against all but the largest invading armies. Build up land units there and spread out. In mid-game, use summons to supplement your natural and indy troops.

But against the troops you will likely find on land (ie. Poison hydras, Vans, Magma Children), these troops are not enough; Oceania needs more. You could burn a few hundred gems on sea king's courts, naiad warriors and winter wolves, take a few provinces on the land, and then get smacked back into the ocean once whoever you're attacking actually bothers to get together a force to take out your army of chaff. That's an investment that will never pay off. Be smart, build clams.

You can equip your Triton Kings with air-breathing Amulets of the Fish and Water Bracelets which gives you a minimum 5 water mage that can spam-cast lots of land-based AoE spells like falling frost. And you'll have lots and lots of them, because you've already dominated the oceans. And they are going to be hella-tough when they get on land because you've got a bless strategy going for them as well. Once you've got the Alteration tree researched for defensive buffs, that's when you start making Amulets of the Fish for your hippocampi-rider CAPTAINS as well.

Summons
Oceania has the problem that many summons can not be cast underwater. So you need a land province to open all possible summons. Also, concerning water-based summons, much of your magic is centered around water, so there is competition for those water gems. Empowering a powerful amphibious chassis and using it to summon land-based troops might be the best thing you can do to support your independents.

Early Game Only these guys can turn the tide in some battles, but by mid-game are generally under-powered. Questionable Gem Investment employ at your own risk. Squad Troops the following summons are notable because you gain a larger number for a single mage-cast: Thugs Pretender Summons it's worth taking the magic paths on your pretender to get these. Note that all of them are only summonable on land.
 * Pride of Lions (Conj-3) for 25N gems you get 17 lions with one cast! While by no means invincible, these guys will give your early land armies some teeth and increased staying-power vs normal troops. Can only be summoned on land.
 * Winter Wolves (Conj-4) Ethereal units with a freeze aura, also nice because you get a bunch of them per cast. Combine their tactics with other chaff units that draw enemy fire, the wolves move in and are immune to your falling frost artillery. They are quite effective in the early phases of the game when your opponent is unprepared. Once your enemy has a counter, they are quite squishy. You can only summon them on land.
 * Ice Drakes (Conj-2) They rout easily and are kind of pricey, but in large numbers their ranged frost attack can be deadly if your opponent doesn't have a counter. They are useless vs cold resistant units and most players will expect Oceania to be using cold magic, which makes the gem investment questionable. If you do use them, make sure their commander possesses a Horn of Valor, or use the Berserker spell.
 * Sea Trolls (Conj-6) Upside: high HPs, just as good on land as well as sea, poison immune, regenerating, 1 sea troll for 1W gem is excellent value. Downside: Sea trolls are expensive to maintain in large numbers, are vulnerable to being mobbed by smaller units, and are quite weak with bad defense and attack especially against land armies of HI. Their only strength lies in their life points so they're good for making meat shields, but it will take a lot of mage-turns to summon enough for critical mass. Only use them if you can properly employ spells like Fog Warriors.
 * Claymen (Ench-4) mediocre poison-immune fighters, these guys are most notable because they can be summoned underwater and each W4E1 Triton King with a Water Bracelet can summon 9 of them for 5 gems. Their regeneration is kinda cool but mostly doesn't help them much. But they have 0 encumbrance and don't tire at all, so you might be able to leverage their usefulness in battle using Curse of Stones, Mossbody, Poison Cloud, etc. for which you can certainly mass a lot of them to try that.
 * Kydnides (Conj-5) Also in the water gem competition are these Naiad Warriors. They cost 30 gems for 15 units with Awe. They are very durable and useful both in and out of the water. However, they don't seem to kill much, so they are better serving as blockers in the center of the army, with trident-armed mermen on the sides.
 * Sea Kings Court (Conj-6) You really don't need this guy, but he makes the list because he comes with an entourage of 15 Sea Trolls, useful in a pinch if your fortress is beseiged. You've got plenty of W4 mages who can become amphibious for less gems. Sea King's only advantage over your national magi is he has feet.
 * Manifest Vitriole (Alt-6) these guys are one of the primary reasons you need to get your Amber Clan Mages onto land asap. Big nasty poisonous ethereal lions! You will be researching Alteration for battle buffing anyways, so win-win. Can only be summoned on land.
 * Queens of Elemental Water (Conj-8) these regenerating ladies are quite powerful when fully kitted-out with magic weapons and a Robe of Shadows. One of them is already amphibious and each one is a good chassis for empowering or prophetizing. They will be a big help in taking and holding coastal provinces from determined counterattack. They can only be summoned underwater, so you have a pretty good chance of getting all three.
 * Lamia Queen (Conj-6, needs N5D2) are a great way to diversify strongly into Death magic and Blood using your surplus of nature gems! These gals also open up some new interesting summons for Oceania. While it is certainly possible to boost your Pretender into summoning Lamia Queens, you can get them much faster if you simply take those paths from the start. Note that Spectres also offer magic diversity with death, but they require D gems to summon, so might be less accessible to you than Lamia Queens are. Both give you a wide range of magic.
 * Thematically, if you think Oceania should be something dark and cold and deep and chaotic, like the sea itself, then Death magic synergizes well: Undead are both amphibious and cold resistant. It can be fun to imagine Oceania sending the corpses of hundreds of drowned sailors out to drag their former friends and neighbors beneath the waves. This could be extended to Hidden in Snow where the Unfrozen undead of a thousand cruel winters take their revenge on those whose blood still runs warm in their veins.

Diversified Summons once you have some new path combos on your mages, you should be able to summon these:
 * Spectre (Conj-6, needs D3) hold on we just said we were going to make Lamia Queens instead, right? Well, one reason you still want specters is that eventually you will summon one with E1/S1 random picks. Give him a dwarven hammer and start mass-producing Crystal Matrices/ Slave Matrices for battlefield communions.
 * Treelord (Ench-7, needs N5) these guys work best used as defensive casters, since they can't move once they are summoned. But that is exactly what Oceania needs to defend it's hard-won land beachhead, and you certainly have the nature gems to do it. Biggest downside is researching up the Enchantment path to get them. Empower them to S1 so they can cast Body Ethereal, Astral Shield, Personal Regeneration and Personal Luck and they become very hard to kill. Astral allows them to teleport to new provinces as well. Technically, with boosters your N3 random mages should be able to summon them, but if your pretender can summon Lamia Queens, s/he should be able to summon these as well.
 * Fairy Queen (Conj-8) also summoned with N gems, these gals are powerful Air magic casters in their own right. They are a game-changer for Oceania, opening up Fog Warriors, Arrow Fend and other powerful battlefield spells. Thus you won't be needing to boost Triton Kings for air casting, and you can save your air gems for Amulets of the Fish.
 * Golem (Const-7, needs S3E2) kitted-out with magic items they make great thugs, since they can self-buff Body Ethereal, Astral Shield and Personal Luck. You've got the S gems from clamming to do it.
 * Elemental Royalty (Conj-8) if you are taking some minor bless on your pretender anyways, make sure to try and get these. Kings of earth and fire offer strong magic casters in paths where you are weak, and they are all strong chassis for thuggery/SC.
 * Manikins or Mandragoras (Const-3/5) both require N gems, which you have plenty of. The Mandragoras are superior fighters, but you will likely get more Manikins for the gems. Both have a magical sleep attack which can be quite powerful.
 * Catoblepas (Conj-7) needs W gems, of which you should have many. Poison-clouded trampler with a death gaze. Great unit for sowing mayhem in the enemy ranks. Cast Quickness and Fog Warriors on it, then let it loose!
 * Call Wraith Lord (Conj-7), which in turn generates ghosts. They compliment Sea Trolls and other frost-resistant units very well.
 * Abomination, Tarrasque, Tartarans (Conj-9) if you have the right gems, use them.
 * Leviathan (Ench7, D3W1, 15 death gems) Summons an undead asp turtle. Must be summoned underwater, but it's amphibious so you can bring it on land. Raid from the water, destroy temples and then scuttle away. When properly supported, they make a non-retreating trampler, useful vs glamour units! Mindless, hp 143, prot 19, MR 13, 10 action points. Make sure to cast Quickness on it first thing.

Bless
Some would argue that since Oceania's sacred cavalry are aquatic only, and the sacred Triton commanders have a tough time coming onto land, this is a reason not to use a bless strategy with this nation, since the points you spend will not directly help you in the later parts of the game. On the other hand, almost all your sacred units can be summoned in every underwater castle with a temple, so it is unfortunate not to take advantage of this quality inherent to your nation. After all, most players are prepared to spend a few gems outfitting a thug, so our thugs will be outfitted with Amulet of the Fish. The upside to doing this is that if your opponent wins a battle and picks up some magic items, these amulets are useless to him.

Consider what you get with a minor bless, specifically with respect to your Triton King and Triton Prince: A fire bless raises the attack skill of both units from 13 to 15. Once the units start gaining veteran status this will go up even higher. Air bless gives us 20% missile protection, which is pretty blah but we are likely to be using Arrow Fend anyway. Water bless gives us 18 and 19 defense skill, respectively, which is quite good ro avoid melee damage as long as our size 3 units don't get mobbed by enemies. Earth bless bestows 2 recuperation, which gives our quickened blessed troops more staying power in long battles where they are out-numbered - a very likely occurrence. Astral bless gives us MR of 19 and 16 respectively, which is definitely way above average. Nature bless will give us 2 and 1 hp regeneration/round respectively, which helps melee troops vs stray arrows and poison attacks, but becomes especially significant for battlefield Communions once the communion slaves pass out and start taking damage (see appropriate section below). However, Oceania has plenty of N mages to lead a Communion who can grant Personal Regeneration to all the slaves. A Death bless works with all battlefield damage as long as the unit doing the damage is blessed. Blood bless gives us 19 and 15 strength, which is mostly significant in the early game vs heavily armored enemies. Once you get weapons of sharpness or wield a brand, the punch-through power of your hit won't be as critical.

So of all those, a W/E/S bless is likely most useful for Triton King and a F/W/E/S bless for Triton Prince. A death bless would be nice to have for both (likely more relevant to Triton King for AoE damage and remote casting), but tbh it is preferable to kill enemies outright rather than give them afflictions.

Research

 * At Start: Start with Evoc-1 so your Amber Clan Magi can cast Geyser, just in case you get rushed. If you get involved in an early war, you probably want Alt-1 for Eagle Eyes and maybe Conj-1 for Tanglevine. Otherwise, research up to Conj-4 to grab the lower level summons on the way to get Voice of Tiamat, if you are remote-searching, and Winter Wolves if you have a land problem. If you take strong magic scales, it is quite realistic for Oceania to get to Conj-4 by the end of year 1.
 * Gem Gens: As soon as you have an Earth Gem income, go for Constr-2 to be able to forge Dwarven Hammers (take E3 on your pretender), Astral Clams and Fever Fetishes.

In no particular order, you can research the following, depending on the situation:


 * Construction: You are mostly interested in this path for forging, but there are some interesting synergies. Much of your magic on land requires boosters, so you'll want to equip your Mermages before setting out.
 * Const-3 Legions of Steel (E3) and Manikins (N1D1) empower or use Lamia Queens
 * Const-4 Thistle Maces (N2), Earthboots (E2) and Amulets of the Fish (A1W1). Crystal Matrices and Slave Matrices (both E1S1) are important for advanced spellcasting using Communions, but you will need to empower or use your pretender.
 * Const-5 Mandragoras (N2D1)
 * Const-6 Water Bracelets (W1), Fire Skulls (F1D1)
 * Const-7 Golems (S3E2) likely only possible if you took those paths on your pretender.
 * Battle Magic: If you feel you need stronger battle magic, there is no really quick-fix. Much of the stuff in the Evocation school doesn't work underwater. Try researching strongly into Alteration.
 * Alteration-3 gives all your various magi Protection and Numbness which is an excellent spell vs non-cold resistant enemies.
 * Alteration-4 Quickness
 * Alteration-5 Wooden Warriors and Bone Melter, both need N2.
 * Thaumaturgy-2 Berserkers and Sleep, requires N2.
 * Thaumaturgy-3 Panic or Sailors Death ditto for N2 or W3 casters.
 * Evocation-3 Sleep Cloud, once again it needs N2.
 * Evocation-4 Water Strike, an underwater alternative for damage vs cold-resistant enemies.
 * Summons:
 * Alteration-6 Manifest Vitriole (W2F1)

Strategy A
Your tritons provide a sturdy ocean-only expansion force with 15+ hitpoints and good protection. Things get a lot harder when you want to crawl ashore, as you well then need to use merfolk (with only 10 hitpoints and either unimpressive defense or unimpressive protection). You may want an amphibian combat pretender to help with early expansion (which is often slow given the limited options underwater) and with coming ashore.

Given your difficulties getting on land, the game is likely to be a long haul for you. Your success will mostly be determined by your starting position. If you're in a large ocean with good magic sites, you can conquer the ocean, turtle up, start your own clam and fever-fetish economies, and have some chance at keeping up with your terrestrial competition. If you're in a smaller ocean, you'll need to establish a defensible land footprint soon, or you'll be in big trouble. Even if you do establish a footprint, your terrestrial troops are unimpressive, so expansion will likely be a challenge.

Scale Design
You're likely to be in it for the long haul, so a death scale is probably inadvisable, and growth may even be advisable. You probably want one magic, to keep research going. Order and productivity are both good to have.

It may be reasonable to start with a relatively weak dominion (4-5 candles), and count on your bishop fishes (120 gold for an aquatic 3-holy) to preach your territories into white candles. A bishop preaching in a temple will keep your candles in a territory high, even in the face of strong encroaching dominion.

Pretender Design
You can take a dormant sacred statue for strong economic scales.

For a super-combatant you probably want the Wyrm, the Ghost King, or an amphibian titan. It's hard to say which is worse: the woeful economy you get having your SC awake, or the risk of missing a crucial window for terrestrial expansion you face if your SC sleeps through the first year.

Since your sacred troops are aquatic only, a bless-strategy is inadvisable.