Heart-derive is a jack-of-all-trades term used to describe creatures normally associated with the heart. The most common of these creatures are the Heartless.
Fleshbodies are a type of Nobody only they're made out of flesh. Fleshbodies are savage and bloodthirsty. They appear as if their flesh stiched together, but not in a random order, more like the bodies of Nobodies.
Biters- they are the most carniverous of the fleshbody they have one huge mouth adorn with fangs covering the torso and snake liike head fill with teeth instead of hands (oddly the mouth on the head is sealed shut.) they crave the taste of flesh, if a victim is bitten, they are automatically paralyzed by a toxin that stiffens the boy so the Biters can eat. there large mouth can also spit huge globs of acid out.
Fire-breather- zombie-ish creatures that have what look like gas-tank strapped to there back. and a liter pocking out there neck sticking next to the mouth. when they breath out they unleash a powerful turret of flame that can reach to 60 feet. despite that ability they move extremely slow and there ability to dodge is slow.
Ninavidets is what happens when a person gives into the hatred in their hearts. When a person can only feel hate and anger it just consumes him or her. This destroys every emotion in their heart and soul, and only leaves hatred. This when a person becomes a Nenavidet. Nenavidet is the Russian word for hate. Nenavidets only show hate, because thats all they have: hatred!
Nenavidets look like the person they once were, but they have generally darker skin. Their eyes are a dickly purple, and their pupils are a yellow slit. Their fingers generally become clawsm, and their teeth tend to sharpen. Nenavidets never smile.
Because they only have hate in their hearts, Nenavidets are vicious and bloodthirsty. They attack and kill on sight. They'll kill anybody, including family members, and former loved ones. They tend to band together, becoming little more than a pack of wild animals. Intelligent animals. They still retain their intelligence.
Nenavidets are physically stronger and faster than normal humans. They often use their claws as weapons, but they can use other weapons as well, including machine guns! They sometimes use Gear Grinds, the opposite of a keyblade, which turns people into Heartless! Nenavidets have been known to bully Heartless into becoming their slaves. Nenavidets are single minded (despite their intelligence) in the destruction they cause. The only thing they ever do is travel from world to world and spread blood-shed everywhere!
Pure-rage, ninavidets that have givven fully to there rage and show several traits of Wolf, scorpion, and Baboon. they act as the warriors.
Less-rage, creatures like you mention that act like the brains intelligent creatures that no the art of manipulation well, they are not to be underestimated, they can easily kill those that disobey, bored or downrightt ** them off. they are the ones capable of using the Gear Grinds