Hiei is a male fire demon born to a race of female Ice Maidens. The Ice Maidens reproduce every 100 years asexually, always giving birth to a female. A male child is born only if the Maiden has had sex with a male, which is forbidden in their society. Hiei was born a twin to the Ice Maiden Hina. As her children were born Hina wept two tears which crystallized and were given to the babies. Hiei was thrown from the floating Ice Domain to his supposed doom. He does manage to survive, though, and grows up in the wilderness where he develops a thirst for killing. The only time he finds peace is looking at the tear from his mother. He soon decides to find the ice domain and take revenge on the women who cast him out. During a battle his tear stone is lost and, realizing he must now find the stone as well as the Ice Domain, Hiei goes to the Osteopath Shigure and has the Dark Eye implanted in his forehead which gives him many powers, including hypnosis, telepathy, and clairvoyance or remote viewing. Even with the Dark Eye, Hiei cannot find his tear stone, though he easily finds the ice domain. When he gets there he finds his mother's grave and his lust for revenge fades. He is told his twin sister has run away and decides to search for her as well. Hiei wields a sword, has superhuman speed and can produce and control fire. During the Dark Tournament he taps into the unruly fires of hell, known as the Dark Flame of the Overlord, which he eventually masters