The Isle of Fire subquest can only be accessed if you have the Forge of Virtue add-on disk. Most of the newer editions of the game (The Complete Ultima VII, Ultima Collection, etc.) include the addon.
How to get to the Isle of Fire
At the time when you start the game, there will be tremors. Iolo comments that maybe Lord British knows what's the reason behind them.
When you talk to Lord British, it turns out he does know the reason: Isle of Fire has recently risen from the depths of the sea. He gives you deed to his ship, the Golden Ankh, as well as a magic crystal.
The Golden Ankh is anchored on the Vesper pier. Be sure to check the ship's hold, it also has a lot of helpful stuff.
Once you sail south from Vesper, you see more of the unstable islands; obviously, they're not on the map, but they're under the band of text. Circle the biggest island to south side, and sail north through one of the narrow gaps. Such gap is almost aligned with the north tip of Magincia island, less than half-a-screen to the west. You end up in a cove where you can drop the anchor. Once beached, head north to the Castle of Fire.
Castle of Fire
The west side of the castle contains Erethian's room. He will provide the Avatar with background information about the castle, the Tests, and the Shrine of Principle. Opposite of Erethian is a mirror and a cylinder-type object. The Avatar can examine both and discuss them with Erethian.
At the end of the main hallway lies the Shrine of Principles which contains three statues that control the tests. The Avatar may talk to each one to initiate a test. The two Moongates lead to the Test of Love and Test of Courage, left and right respectively. The Test of Love's Moongate is accessed through Erethian's room by opening the wall. The statue for the Test of Truth simply teleports the Avatar and party to the appropriate area.
Test of Truth
- I am forced to wonder how this maze of tunnels can demonstrate Truth. --- Written on a scroll near a corpse
After arriving, exit through the fake wall to the south. The Avatar will now be in a room with a skeleton on top of an "X" made of stones. Do not step on the X for it is a trap.
Continue to the west and a metal gate will be visible. When you pass it, the true test of true already started.
There are several (seven) small rooms holding "false" lockets; when you pick up a locket and put it in your inventory, it disappears as well as all the decorations of the room. From this, you are supposed to understand that your goal is to find the one true locket. Good luck!
- Only appearances are deceptive (therefore, you should look for something that could, theoretically, cover your eyes and prevent you from seeing appearances)
- North is the way (once you found the aforementioned "something")
- (Scroll) ...I have seen far too much in the way of deception and falsehood. I am forced to wonder how this maze of tunnels can demonstrate Truth... (indeed, it does not; truth is before the entrance to these "tunnels of falsehood")
- Trust not always the obvious path (it refers to two locations: one is a nearby fork, the other one is the path to the solution)
- Thou dost not wish to see this (it means two things: one is a warning about a nearby teleporter, but also that you went way past your goal)
True but unhelpful:
- Truth is truth
- The keys to truth (name of the cell puzzle)
- Follow the fire (wooden sign)
- Well done
The wooden sign marks the entrance to a labyrinth of invisible barriers. To the south-east is a corpse and a scroll where the author wrote his frustration for being unable of understanding the link between the principle of Truth and this test.
If you can lower the drawbridge and get past the Keys to Truth, you can find a few useful items. Still, the solution to the Test of Truth lies somewhere else.
- A Ring of Regeneration just past the metal wall. Caution should be exercised as all the items in the room are trapped.
- A Glass Sword near a teleportation pad. This is to the far north in The Keys of Truth which requires following a river and crossing a draw bridge to enter. Various monsters are locked in cells and the Avatar must obtain each key in success to unlock the way to the Glass Sword (or just use Telekinesis on a switch).
- Six (6) Burst Arrows and a Ring of Protection in a locked chest to the extreme north. Past the glass sword, take the teleportation pad to arrive in a new area. Be cautious of traps and watch for hidden teleportation spots. Keep following the path. Golems stand guard somewhat near the locked chest, but can be avoided completely.
The scroll at the south-east end of the invisible barriers suggest these are the "Tunnels of False-hood". Thus, you want a "true hood". Since only appearances are deceptive, you should locate the hood. From there, trust not the obvious path and north is the way, that is: walk north into the wall. The secret passage has two turns, but it leads to the true locket.
Test of Love
After exiting the Moongate, head to the sandy southeastern section to see a Golem standing near another, fallen Golem. Initiate conversation with the living one and discover his name is Bollux while the dead Golem is named Adjhar. Agree to help him.
Read the book Bollux hands to the Avatar. A scroll will fall out of the tome; be sure to pick it up and read it. There are some additional books in the house to the west that provide background information, but those are optional.
Pick up the bucket at the well to the north if the party lacks one, then head to the door at the north end of the desert/quarry. Pass through the mine heading south and pick a pickax along the way. Exit south into an open area and the Avatar will be teleported to a hallway.
Head south until the party reaches a tree growing out a rock, the Stone of Castambre. Place a bucket at the base of the tree and hit the tree with the pickaxe. Collect the bucket of blood and go back to the quarry. Double-click on the bucket of blood and place some on each of the rocks.
Back at the quarry, attempt to cast the spell by double-clicking on the scroll. A stone heart will have to be placed inside Adjhar's body. When done, double-click on the scroll again.
Greet Adjhar and agree to help him. Make sure to show the book to him when asked. Go back to the Stone of Castambre and use the pickaxe on it again to receive a stone heart. Use the pickaxe and bucket together to obtain even more blood. At the quarry, place the heart in Bollux and perform the whole ritual once again.
To finish the Test of Love, talk to Adjhar. Ask him about his job and he will offer the Talisman of Love to the Avatar. Accept or wait to get the secret bonus treasure.
A secret room of treasure can be found during this Test. The top-right corner of the Stone of Castambre contains a lever which is barely visible (one-pixel wide). Clicking on it will open a hidden passage in the hallway. Enter it to find a Firedoom Staff, a Death Scythe, and Glass Swords stored on a corpse.
Note that the Moongate ceases to function after completion of the test, so the Avatar should recover these treasures either before completing the mission or take the flying carpet to the Stone of Castambre afterwards. It is possible, though exceedingly difficult, to land near the stone by finding a suitable patch of grass.
Test of Courage
Before starting the final test, some preparation may be necessary. Completing the Tests of Love and Truth increases the Avatar's combat and magical abilities which will be useful during the Test of Courage. To fight Golems, the best melee fighters should be equipped with magical armor if available and heavy weaponry such as the Death Scythe. A collection of sleeping potions should be brought for dealing with dragons and other annoyances. Sufficient reagents and knowledge of the Mark and Recall spells are recommended. Marking the main hall of the Castle of Fire can save the party when backtracking.
After exiting the Moongate, the party will be behind a locked gate. When ready, pick the lock and head toward the main room. As the Avatar enters the main room, a mage with summon a Liche to attack the party. The Liche cannot be directly attacked due to invisible walls, but indirect spells such as Magic Storm work well. Also, it can be avoided by letting the party (but not the Avatar) charge into the room before the summoning, putting the mage to sleep, or simply attacking quickly and disrupting his incantation.
The main room also contains weaker monsters such as skeletons and headless which the party can dispatch easily. However, at the far right of the room is a locked gate with a pair of Golem guards. Try to avoid letting any members near them just yet. After all the weaklings are dispatched, search the mages' bodies for keys to the east gate (only one is needed as both have the same exact key). Search the bodies around the red Moongates for pieces of magic armor (gloves, leggings, gorget, and torso). Equip as necessary. The Moongates apparently go nowhere.
The Golem guards may be a tough battle, particularly if the party lacks magical armor and weapons. They are resistant to status effects like Sleep and Curse. It may be possible to sneak or run by them, quickly opening and closing the gate (be sure to lock it as Golems can open doors). Try to fight Golems one at a time to maximize damage and minimize risk. Cast Protect All and Mass Might if those are available. With increased mana from the Test of Truth, the Avatar should be able to throw out some good offensive spells as well.
Past the gate, the party will be in an area with spiders and scorpions. The path west is blocked by a double wall. There are two levers in the northeast arachnid dens. Pull them to open the way forward.
Be prepared to fight dragons as 1-3 of them inhabit this area. Deal with them using blue potions or Sleep. Enter the room with the crystal ball and look at it (doing this before fighting the dragons may cause two of them to disappear). It should show a key with a Glass Sword below it. Go to the corpse in the dragons' lair and collect the magic shield. Lockpick the chest and take the Glass Sword. Place the sword in the area directly below the crystal ball. A key appears. Take it, it opens the northern door.
Continue north into the side hallway and take the magical helmet, but don't equip it. Go south down the hallway and defeat the Golem. Continue right, lower the metal walls and defeat another Golem. Directly right of these double-metal-walls is a dragon bone that gives free ammunition to muskets, but the main route runs south through some slimes.
Enter the hallway with the broken columns, swap the regular helmet with the magic helmet. Then, go all the way back to the first pedestal and place the normal helmet there. The northern walls should open and allow the party to enter. To collect the magic helmet, Mark a Virtue Stone somewhere within the metal gates. But don't collect it unless the party can Recall to the main hall of the Castle of Fire.
Immediately upon entering the northern area, a charred body with a magic axe on it can be found. Continue into the pillars and search the bodies for a Glass Sword and a Triple Crossbow and some bolts. Don't quite enter the room because that initiates a conversation.
This dragon, Dracothraxus, is just as susceptible to sleep potions as normal ones. Hit her with one and then attack. After the battle, Dracothraxus offers the Ether Gem to the Avatar. Take it. The dragon retires to recharge her power and the party must return to the main hall of the Castle of Fire. The Test of Courage is not over yet and the Avatar must obtain the "artifact of power" to continue.
The party can collect the magical helmet, but be sure to have the northern area behind the metal walls marked in order to return later.
Forging the Black Sword
Back in the main hall, talk to Erethian and ask about the "powerful artifact." He will summon some blacksmith equipment and an incomplete sword. Approach Arcadion with the Ether Gem. To free him, equip the gem as a weapon, double-click on it, and target the mirror. The now daemon-gem serves the Avatar with the ability to restore/build-up Mana by partaking of the daemon's power.
At the forge, work the bellows until the sword becomes extremely hot (bright red). Move the sword to the anvil and hold the hammer. Hammer the sword until a message regarding its sharpness is received. Continue once or twice more until the Avatar receives a message about imbuing the sword with magic. Talk to Erethian about the Black Sword and the topic shifts to binding the daemon-gem with the sword. To accomplish this, hold both the sword and gem in the Avatar's hands and talk to the daemon.
When bound together, the daemon-sword can cast certain powers such as Fire and Death. To access these powers, open the paper doll and double-click on the black sword.
With the Black Sword, the Test of Courage can finally be completed.
Simply Recall to the northern area of the Test of Courage. Meet Dracothraxus again. Talk to the Black Sword and ask it to use Death on Dracothraxus. Now enter the blue gate to the north and enter a hallway with statues. Simply take the Amulet of Courage and the trial is complete.
After receiving the final gift of power from the keeper of Courage, it orders the Avatar on an emergency mission to find the Talisman of Infinity. Talk to Erethian about it, but he needs a scroll. It's right in his room, so pick it up and ask Erethian again. Erethian will stop communicating partway through, so switch to the Black Sword/Arcadion as he knows something about it.
Arcadion says that two lenses, lit torches, and the Amulets of Principle are needed to interact with the Infinity Talisman. The two lenses can be found in the British Museum. Recall or gate there and take them. Use Recall to return to the Castle of Fire. The lit torches should already be in place. Place the lenses on either side of the Dark Core. Stack the talismans on top of the Core; make sure it is in a pie-like formation. The order from clockwise is: red, yellow, blue, and a blank spot in the top position. The ribbons on the amulets should be facing outside the "pie." If nothing happens, try adjusting the position of the lenses.
Once everything is in the proper position, a scene will play out. Afterwards, return to the mainland via the party's conveyance of choice and speak with Lord British. He will reward the Avatar with even more strength.