Sumio Tohba is the brother of Rumi Tohba. He is the lover of Kyoko Kazan. He is jealous of Ryo Kazan because of his relationship with Kyoko. He makes a contract with Mithra and murders Kyoko. Mika had a crush on him but it is slowly transferred to Ryo instead. He is killed early on. He is very indecisive. He is killed by Kimika Takahashi, a woman he impregnated, in a double homicide at the Lost Highway.