Prison Keeper

The Prison Keeper is an Emblem Heartless that is found in Kingdom Hearts II. It is one of the bosses at Halloween Town. It can swallow others to power up its attacks.

Kingdom Hearts II
A Heartless called forth in Halloween Town by Maleficent to get revenge on Sora.

It held Lock, Shock, and Barrel captive while dealing various elemental attacks.

Kingdom Hearts II
After Maleficent resurrects Oogie Boogie, she leaves Lock, Shock, and Barrel behind to deal with Sora and Jack Skellington, and summons the Prison Keeper to assist them. It swallows the children to empower itself, but Sora, Donald, Goofy and Jack manage to defeat it and release the children. With their usual disloyalty, they immediately reveal Maleficent's intentions to the heroes.

Design
The Prison Keeper is a large, seemingly mechanical Heartless that seems to be made out of metal, and is thus predominantly shades of grey, black, and silver. Its large, egg-shaped head has a jagged, gaping maw and glowing eyes that are triangular spirals. Its face is not one uniform color, and seems to have been broken, as there is a crack between its eyes that appears to have been stitched or stapled back together. It has a long, twisted antenna sprouting out of the top of its head that appears to be wrapped in bandages. Its Heartless emblem is at the base of this antenna. Its long arms are connected to the bottom of its head, are mostly covered by metal "sleeves", and its hands seem to be made of bone. A large, metal cage holding the three children is suspended by a wire that hangs from the bottom of the Prison Keeper. The cage resembles the one that Lock, Shock, and Barrel use to travel Oogie's Manor in The Nightmare Before Christmas and Kingdom Hearts. There is a large, black knob on either side of the Heartless's head that seems to operate a the winch at the Prison Keeper’s base.

The Prison Keeper's name refers to the cage it holds the three children in, which is reminiscent of a prison cell.

Strategy
Equip all of your Aerial abilities, and maybe the Hero's Crest (unless you want something with better magic.) Also, you should equip Reflect to your shortcut menu. Fighting the Prison Keeper is all about maintaining pressure, so you should repeatedly assault it with air combos and limit attacks. If he tilts his head back approach him and use the inside combo Reaction Command to stun it.

After a while it swallows one of the three, and its attacks depend on the child:
 * Shock: The Prison Keeper will spin its arms around, rising up and then falling down while spinning around the arena, firing lasers. Its arms glow a dark yellow. This is easy to avoid, just get close and attack.
 * Lock: It will shoot large fireballs out of its mouth and hands from a distance. These fireballs can be deflected to damage the Heartless. The best way to counter this is to knock them back by using Guard or hitting them back. Reflect, although useful, is not recommended. During this attack, the Prison Keeper's arms will be red.
 * Barrel: It will use a powerful biting attack on just Sora and slash madly. Its arms glow green. Keep your distance and use Thunder.

Near the end of the fight, it will swallow all three and use a mixture of attacks: fireballs from its eyes, slash attacks, and it will spin. Don't even get near it now. Instead, use Wisdom form, keep your distance, and continue strafing (don't stop moving) until it is defeated. Donald's Limit is also helpful here. If you run out of MP, getting to the top of Spiral Hill may be the best way to start attacking the Heartless with your Keyblade.