 Even when decapitated, Tenzen can regenerate if someone holds his head to his body while his symbiote seals the cut.In the manga, Ogen tells Oboro that the symbiote creature is Tenzen's twin brother with whom he merged with inside their mother's womb shortly before being born.In the anime however Ogen stops just before telling Oboro where she believed the parasite came from, leaving its identity ambiguous.