Cerberus/Gameplay

Cerberus is is a three-headed hellhound who guards the Underworld. He first appeared as Hades's loyal pet in Disney's Hercules, as a guard dog to the Underworld. Cerberus serves as a boss in Kingdom Hearts, Kingdom Hearts II, Kingdom Hearts coded, and their remakes.

Kingdom Hearts
It is important to be able to climb on top of Cerberus's back, in order to avoid its Dark Breath attack and his Fireballs. Alternatively, you may use Dodge Roll to avoid Cerberus' Dark Breath attack, or even deft running. Lock on to one of the outside heads and remain to the monster's side.

Use the Guard ability to deflect its fireballs. (Note: going under Cerberus' back when it uses Dark Breath will not work.) Use its back and the stairs as places to heal yourself, which is important to do often. Be sure to have a load of items like Ethers and Potions, or be sure to equip a Keyblade and items that give you at least 10 MP.

Do not rely on Donald for healing, as he dies quickly, especially in the first battle. Be sure to lock on and attack the heads on the side, not the middle head. Use Dodge Roll and/or Glide (or alternatively, Superglide) often to get away from his Bite. After several attempts to bite, it will stand on two legs and roar in the air. When he does this run away from it, or be ready to jump, as it is about to use a powerful shockwave.

Keep attacking the heads with your Keyblade and use a combination of Fire and Thunder magic to finish it off. While attacking the side heads, you can cast Aeroga on yourself to increase the damage. You receive the Inferno Band for winning this battle.

Kingdom Hearts II
Cerberus is by no means an easy opponent, but at the same time, it should not cause the player too much trouble. The player is only forced to face it once, but does so with Auron alone, meaning no drives. Also note that this fight is held in the Underworld, meaning drives are off limits until the Olympus Stone is obtained. The first thing Cerberus will (usually) do is jump right in front of Sora, so be ready to deliver an aerial combo.

Sora will be thankful Auron is here, as his Bushido is immensely useful; although Sora should try to hit two heads with it. The Star Seeker Keyblade is recommended, as it's aerial boost will be helpful while performing aerial combos. Cerberus isn't keen for a chat though, as he often swivels around leaving you nothing but his back, preventing damage.

For those who use the Keyblade more then magic, just lock onto a head and start using combos, and Bushido whenever possible. If the user prefers a magical route, use thunder on one head until you have almost no MP left, then use Bushido. You are often entered into a contest of survival when Cerberus tries to eat you, when this happens, use the reaction commands to make things easier, and this contest looks brilliant as well.

Cerberus has just over two bars of HP, which isn't that large, although much bigger then Sora's HP. And if this precious HP gets low, stick to the edges and use quick dash to avoid Cerberus when it jumps over to you. The Get Bonuses are an HP Boost for Auron, and Dodge Slash for Sora.

In the Cerberus and Cerberus Paradox cups, you fight it alone, although you can still use drives. Sora can use Valor Form to hammer some sense into him, or play it safe and shoot magic bullets at it with Wisdom Form. Master Form is the most recommended form though, for some reason it seems built to fight Cerberus. All of the abilities Master Form has equipped will help Sora defeat Cerberus. Of course Final Form is the best, and Sora should use the form if it has it, but that isn't very likely.

Since the Cerberus and Cerberus Paradox cups are timed battles, you should be wary of the time constraint. If you have Final Form, use it. Every single movement is an attack in itself, and this should buy you time to keep on mashing. Do not compromise unless you have managed to take all the lesser enemies out within seconds.

Kingdom Hearts Re:coded
Cerberus in Kingdom Hearts Re:coded is quite a formidable opponent. His attacks deal good amount of damage, and he can attack Data-Sora, Hercules, and Cloud at the same time. Good timing of combos and blocking is crucial in the battle, and command decks should be filled by Cure commands so Data-Sora can quickly heal the party if the situation gets worse. You should use Cures instead of potions, since an immediate battle with Hades is next.

Using attack commands is not recommended as they deal insignificant amount of damage to Cerberus, normal attack combo is the best way to deal damage to the three-headed dog. If several attempts on beating him fail, you can always use licenses. Regen License is particularly useful, and Auto-Life License can be given to Data-Sora to make sure the battle doesn't end soon due to Data-Sora's defeat.

Trivia

 * Although most of the world bosses in Kingdom Hearts: Chain of Memories are the same as in Kingdom Hearts, Cerberus is replaced by Hades, who was an optional boss in Kingdom Hearts.