The Leechgrave's main body is a decrepit, black coffin with pale gold lining. This coffin is surrounded by a large, silver chain, has two large, silver nails driven partway into it, and has a small hole near its top where a single, glowing yellow eye peers out. Occasionally, two large, pale green, clawed hands are able to force their way out of the coffin, though no other part of the coffin's contents are visible. Its Heartless emblem is on the lower half of the coffin, and there are other red patterns resembling claw marks decorating it. This coffin hangs from a pink and red-violet bud with angular, pale yellow spirals for eyes. This bud sprouts four lone, dark green, thorny roots that keep the Leechgrave anchored to the ground.
These roots are the source of the Tentaclaws, the Leechgrave's appendages. A Tentaclaw is a black creature lined by thorns. Its tip is red and it has three black mandibles, each with three curved spikes resembling scythe blades.
The Leechgrave's name references the casket-shape of its body and its cannibalistic behavior. By devouring other Heartless, it steals the hearts Organization XIII hopes to use, thus making it a leech or parasite to their goals. Its Japanese name, "Parasite Grave", is similar to another Heartless boss, the Parasite Cage (パラサイトケイジ). The Tentaclaw's name reflects its tentacle-like body and its clawed mandibles.
Kingdom Hearts 358/2 Days
After finishing a mission to exterminate a Carrier Ghost at Halloween Town, Roxas heads back to the castle. However, as he approaches the portal home, he is startled when a Tentaclaw suddenly bursts from the ground. He defeats the Tentaclaw and goes home, but a month later the Organization learns that all the Emblem Heartless have mysteriously disappeared from Halloween Town.
Roxas is sent to investigate, and discovers that Tentaclaws have overrun the town. He tracks them to their source, and finds the Leechgrave, which had been eating the other Heartless. After a battle, Roxas defeats the Leechgrave and retrieves its heart, but unbeknown to him, he had been watched by Jack while he was brainstorming new scares. The combination of Roxas's cloak and the Leechgrave's tentacles gives him the idea for the Scarecrow, which he later creates. He presents it to Dr. Finkelstein just as Roxas passes by on his way home.
The Leechgrave is slow, large, and rooted to the ground. To attack, it can swing the coffin at Roxas, open it up to slash at him with ghostly arms, fire poisonous pollen at him, or emit a poisonous mist. However, its main mode of attack is to use the Tentaclaws to batter and swallow its opponents.
Make sure to bring Cure/Cura magic and the Auto Life panel. A small stockpile of Fire spells are also a good idea for dealing with the Tentaclaws. The Leechgrave is vulnerable to critical hits.
The most efficient strategy is to remain amongst the Tentaclaws for as long as possible. Move close enough to the Leechgrave that it tries to attack with its ghostly hands, but make sure to move away before it does so in order to stay safe. Immediately after, the Leechgrave will pause for a short period—unleash at least one combo on it in that time. However, if it begins getting ready to use another attack, especially the poison mist or arm-slash, move away quickly. Though the Leechgrave is highly resistant to magic, non-Fire or Cure spells aren't valuable in this fight, so go ahead and cast them on the boss whenever Roxas is unable to get close to it.
After depleting the Leechgrave down to a health bar or two, go after the Tentaclaws, using Fire spells and aerial combos. However, try not to finish off the last one until Roxas hits the Alarm Zone, so that he can immediately unleash a Limit Break on the Leechgrave when it staggers. Also note that in this battle only, the Tentaclaws will get dizzied if their attacks are blocked, leaving them more vulnerable to attacks.
When connected to the Leechgrave, the Tentaclaws serve as its weak point. By blocking the Tentaclaw's bite attacks, it will render them vulnerable to magic. When all four of the Tentaclaws guarding Leechgrave are destroyed, the main body will fall over, leaving it open to attack. However, after recovering from its daze, the Tentaclaws will all regenerate.