Castlevania: Circle of the Moon/Bosses

As is standard in Castlevania (and most games), each area has a guardian. None of the bosses have random item drops, however after defeating most of them, you will receive a relic which will give you new abilities, access to the next area, and allow you to go back and retrieve some power-ups that you couldn't get to earlier.

The Zombie Dragons and Death can be skipped, however it is not recommended. Defeating Death will net you the Cleansing relic which makes the Underground Waterway significantly easier. Defeating the Zombie Dragons will get you the Heavy Ring which is necessary to get to Death, numerous power-ups, and Lilith.

Cerberus

 * HP: 600
 * STR: 150
 * DEF: 100
 * EXP: 960
 * Element: Light
 * Receive: Double

Imagine a puppy jumping on your lap and licking your face. Now imagine a fire-breathing, lighting shooting, puppy the size of a mini-van jumping on you and eating your face. That's Cerberus. He has a specific pattern of attack and changes colors based on his upcoming attack. First, he'll turn red and use his fire beam, then he'll turn blue and release the electric balls and then lunge across the room to a platform and repeat the process. He is invulnerable when he is shifting colors, so don't waste your time or weapons. It's not an opening to attack. The room is fairly high and about two screens long, so you have a lot of room to maneuver (of course, so does Cerberus). There are two rows of three platforms in the room that you can use to avoid his lunges and jump over him.

Attacks:
 * Fire beam: He shoots a narrow beam of fire that sweeps the ground in front of him. He only does this when standing on one of the platforms, so simply stand under hit. If you have an axe, you can throw them at him from below.
 * Electric balls: A couple of large blue orbs drift around the room firing electricity straight down. He's stationary at this point, so you can hit him with your whip.
 * Lunge He'll jump straight forward and cross the room. Don't stand in front of him at this point. If he's on the ground, move to on of the upper platforms, otherwise get on the ground.

VampireKiller
The fight isn't very complicated, though he is strong and can kill you if you aren't careful. His strongest attack is his fire beam, so make sure you are under or behind him whenever he turns red and then just throw axes at him until he moves. In theory, the best time to attack him is when he is controlling the electric balls, as he doesn't move. However, you still have to be careful of the electricity which can catch you off guard if you are focused on attack. When he croutches down he's about to lunge, so get high enough that he'll go under you. You can try kneeling directly in front of him as there is a chance he'll just jump over you.

Magician
If you're feeling lucky, you can try transforming into a skeleton with Pluto/Black Dog and throwing bones until you throw the Big Bone, which will kill him in one shot. The way to do this is from the lower middle ledge. Just remember to change back into a human if you're about to get hit or you'll die in one shot.

If you want to play it safe, use summons like Uranus/Thunderbird or Uranus/Black Dog. In any case, keep a close eye on your HP. You have very low defense and he has very high strength.

Necromancer

 * HP: 500
 * STR: 200
 * DEF: 250
 * EXP: 2500
 * Element: Dark
 * Receive: Tackle

At first the Necromancer is a completely cloaked figure, kind of like a colorful Grim Reaper (how he's usually portrayed, not the version of Death that you'll fight later). He likes to throw six energy balls around and occasionally summon monsters. It's a large room, but since he usually stays high you'll have to attack from the rather small platform in the middle, meaning he can knock you down easily and then swoop around and hit you as you try and jump up. The balls flash before he starts throwing, and he throws one at a time, so they aren't excessively difficult to dodge.

Once you beat him, he toss off his cloak revealing a winged skeleton. He still hovers about, but instead of throwing energy balls he'll turn into a gigantic one and bounce off walls at a high speed. This attack is very strong, very fast, and there is no safe spot to avoid it. Just jump out of the way when you see it coming. It can be easier to avoid if you're on the ground, though it's harder to hit him since he generally comes out of the spin high in the air. He'll continue to summon monsters, but call skeletons instead of zombies. These guys throw bones, and you'll be on the ground more, so slide-kick your way across the floor as they appear.

Keep an eye on your HP and use cards to boost your defense as the Necromancer is a very hard boss, even harder than some of the later ones.

Attacks:
 * Orbs: Six orbs circle him, and they he'll throw them at you. Duck and jump to avoid and then attack back whenever get an opening.
 * Screw Attack: He'll turn into a giant ball of energy and bounce around the room.
 * Summon: He'll call forth bunch of zombies that walk around the ground.

VampireKiller
For his first form, there's a short break between when he throws his sixth orb at you and when he can throw again. Focus on dodging more than attack until he's empty and then just fling boomerangs at him (you can get one right outside his room) like there's no tomorrow. The best time to hit him is when he's summoning since he remains stationary. The zombies that he summon stay on the ground, so they can't hit you when you're on the platform. If (when) you get knocked down, simply slide-kick across the floor to keep the undead population down.

For his second form, all you can do is hope for the best. Jump out of his way when you see him coming and whip/throw weapons at him when he stops. If you're on the platform when he starts to attack, it's usually easiest to avoid him if you jump off the edge and go into the lower corner of whatever side he started on. As before, the best time to hit is when he's summoning, and he summons more frequently. However, the skeletons fire the moment they appear (and seem to have better aim than normal), so you have to take them out as well.

Magician
Unlike Cerberus who had two different elemental attacks, the Necromancer only uses Dark attacks. Just turn on Neptune/Black Dog so all his attacks drain MP instead of HP. You still need to avoid getting hit too much since once your MP is gone he can take away HP again. Another option is to use Uranus's summons, though be careful of using the expensive ones like Thunderbird too much as it can drain your MP rapidly and this is a fairly long fight.

Iron Golem

 * HP: 640
 * STR: 290
 * DEF: 450
 * EXP: 8000
 * Element: Stone
 * Receive: Kick Boots

The easiest boss in the game since he moves so slowly and his attacks are easy to avoid. He has a powerful punch, but he aims high and strikes very slowly, so unless you accidentally jump into it, you shouldn't have a problem. His other attack is to shake the ground (which hurts you a little), and causes gears to rain down from the ceiling. The gears are dropped on random spots so most don't even come close to you. You can also destroy the gears by whipping them.

Attacks:
 * Punch: A slow moving, high punch. Duck to avoid or just stay back a bit. It is damaging if it connects, so be careful.
 * Quake: Hits the ground and gears drop down. Jump to avoid damage from the quake and then face right and whip until they're all gone. There's a slight chance one will land on your head, so just move back if one is coming.

VampireKiller
Just hit him with whatever you've got - boomerangs work best, but axes, holy water, and the standard whip get the job done. Use Venus/Salamander to raise your strength so the fight ends faster.

Magician
Summons are your best best as his high defense can absorb most of your standard attacks since you have low strength. Aside from summons, any attack that stays on one spot for a while and causes continuous damage works well. He's also slow enough that you can probably use Pluto/Black Dog to turn into a skeleton and try and hit him with a Big Bone.

Adramelech

 * HP: 1800
 * STR: 380
 * DEF: 360
 * EXP: 16000
 * Element: Dark
 * Receive: No relic, but you can destroy the statues that block the Underground Galley and Underground Waterway.

One of the hardest bosses in the game, Adramelech takes up an entire room of the Chapel Tower. Fortunately all but his head is in the background, so you don't have to worry about it. Unfortunately only his head takes damage, and it's suspended in the air, though it is thankfully stationary. You'll have to jump to hit him, as even the axe can't reach him when you're on the ground. He has two attacks, however he uses them both at once increase his killing power and carpet the entire area with magic. As such, focus on reducing the amount of damage that you take using cards, rather than trying to avoid individual attacks. Keep attacking and soon you'll blow up his head, leaving only his body to decorate the background.

Attacks:
 * Flying skulls: Skulls that fly. Skulls that fly very fast, hurt you a lot, and attack in large numbers, to be precise. They come out of his hands, and if your under the hand that they come from, they can't hit you.
 * Bubbles: Bubbles that float around the room, making it hard to jump without being hit. They can be destroyed with a whip.
 * Fire: Blankets the ground in flames that is hard to doge and hurts you significantly.

VampireKiller
Even with boosted defense his attacks cause a lot of damage and you can't use Neptune/Black Dog to absorb his dark attacks. The next best option is Jupiter/Golem which makes you invicible for four times as long after taking a hit. This gives you a lot more time to get back up and throw axes and boomerangs at his head without worry about getting hit again. If you are using the boomerang, stand back exactly far enough so that Alramelech's head is precisely where the boomerang turns around. It hangs in the air at that point and will do extra damage (as opposed to just two hits going and coming). Hopefully you've been stockpiling healing items as now is the time to use them.

Magician
This can easily be the magician's hardest boss since even if you use Neptune/Black Dog you'll be knocked around so much that you'll have trouble getting a hit in. Your best bet is to use summons, especially Thunderbird. They cause significant damage, but more importantly you're invincible while summoning. Try and time the summoning so that you set it off right when a barrage of attacks begins, otherwise you might become vulnerable again just in time to get a face full of flying skull.

Zombie Dragon

 * HP: 1400
 * STR: 390
 * DEF: 440
 * EXP: 15000
 * Element: Poison
 * Receive: Heavy Ring

Death

 * HP: 880
 * STR: 600
 * DEF: 800
 * EXP: 30000
 * Element: Dark
 * Receive: Cleansing

Camilla

 * HP: 1500
 * STR: 650
 * DEF: 700
 * EXP: 50000
 * Element: Dark
 * Receive: Roc Wing

Hugh

 * HP: 1400
 * STR: 570
 * DEF: 750
 * EXP: 12000
 * Element: Light
 * Receive: Final Key

Vampire form

 * HP: 1100
 * STR: 805
 * DEF: 850
 * EXP: 15000
 * Element: Dark
 * Receive: Nothing

Demon form

 * HP: 3000
 * STR: 1000
 * DEF: 1000
 * EXP: 0
 * Element: Dark
 * Receive: Nothing