Blackheart

A Blackheart (Romaji: Burakkuhāto; Kana: ブラックハート) is the remnant of a fragile and weak heart which succumbed to darkness but failed to become a heartless.

Whenever a heart is consumed by darkness, the heart will either be corrupted into a heartless or shattered into heart fragments. In the case of a heart that is shattered into Heart Fragments, if the heart contains any memories with a sufficient degree of intensity and longevity, then those memories will animate and materialize the heart's darkness into a blackheart.

As such, technically, a blackheart is neither a blackened heart nor any kind or type of heart at all. But rather, a blackheart is dark embodiment of a powerful and unforgettable memory.

Story
WIP...

Design
As beings composed of a darkness which has been animated and materialized by memories, a supermajority of blackhearts take the appearance of a black silhouette which is outlined with one of the darker shades of red.

However, if a blackheart is composed of either a sufficient amount of memories or sufficiently powerful memories, a blackheart is able to exhibit a more detailed and unique appearance. And if a blackheart is composed of all or even just most of its Somebody's memories, a blackheart is able to exhibit the appearance of its Somebody.

Nature
A blackheart is the exact opposite of a heartless.

While a heartless is a heart which has been consumed and usurped by darkness, a blackheart is a memory which has conquered and imposed itself on darkness. In addition, while the heartless seek to consume and corrupt the hearts of other, the blackhearts seek to destroy the hearts of others and then rebuild their hearts with the fragments of those hearts.

Consequently, the blackhearts and the heartless are diametrically opposed to one another. The blackhearts hunt the heartless in hopes of rebuilding their hearts with fragments of the heartless' hearts, while the heartless resent the blackhearts for destroying the hearts that they seek to consume and for preying on them as well.

As a rule, a blackheart's intelligence is directly proportional to the quantity of its memories. While a blackheart's power is directly proportional to the quality of its memories. So the greater amount of memories a blackheart has, the greater amount of intelligence the blackheart will exhibit. And the clearer and more emotional those memories are, the faster and stronger the blackheart will be.

Notably, among the most intelligent and most powerful of the blackhearts, it is not uncommon for them to reforge the fragments of their heart into armor and or weapons.