Heart is one of the Four Chief Vassals under Shin's King organization, alongside Spade, Diamond, and Club. He's a large, heavyset guy with an unusual body—his stomach is made of some kind of rubber-like material that basically negates most martial arts attacks, which is why people call him the Kenpō Koroshi, or "Destroyer of Fists."
Most of the time, Heart's pretty laid-back and actually more merciful than the other Kingsmen, but he has a serious problem: the moment he sees his own blood, he completely snaps and turns into a homicidal maniac. It's a pretty significant weakness given his otherwise intimidating presence.
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