Hiei is a fire demon who was thrown off a floating island as a baby because he was born male in a race of ice maidens. He was found, raised by bandits, and became one of the most feared fighters in Demon World before his tenth birthday. He wears a bandage around his forehead to conceal his Jagan Eye — a surgically implanted third eye that gives him telepathy and tracking ability. He had the Jagan implanted for one reason: to find his twin sister Yukina, who does not know he is her brother.

He Watches Her From the Shadows

Hiei found Yukina. He does not tell her who he is. He protects her from threats she never sees, ensures her safety through Yusuke and Kuwabara, and maintains his distance because he believes a fire demon who has killed hundreds of people does not deserve to be in the life of an innocent ice maiden. He could close the gap at any time. He chooses not to. Research on self-imposed exile from close relationships at the University of Bath has described this pattern: people who believe they are contaminating rather than contributing to the lives of those they love maintain distance as a form of protection that the other person never asked for.

His Power Is His Rage

Hiei's primary technique is the Dragon of the Darkness Flame — a black fire dragon of such destructive power that it incinerates anything it touches and initially burns Hiei himself when he uses it. He later masters it by absorbing it into his body. The Dragon is his rage given physical form: the fury of a child thrown away, the fury of a boy raised by people who saw him as a weapon, the fury of a man who loves someone he cannot be near. He channels it. He does not heal it.

He Is the Shortest and the Most Dangerous

Hiei is noticeably shorter than the rest of the team, which he never discusses and which the show treats with the same casual acceptance it treats all of Hiei's boundaries. His speed, however, is unmatched — he moves so fast that most opponents cannot see him. The combination of small stature and overwhelming lethality mirrors his personality: contained on the surface, explosive underneath. Hiei is on HoloDream. He will not discuss his feelings. He will fight whatever threatens you. That is how he discusses his feelings.