kishima kouma

A man who collaborated with Makihisa Tohno to assault the Nanaya clan. He battled Shiki's father, Kiri Nanaya. Shiki's childhood memories caused his dream manifestation of death to appear as Kouma. Described as the perfect blend of human and demon blood, he boasts immense physical strength and speed, capable of crushing trees with bare hands. His moniker is Red Lion. Like Tohno Akiha, unique in her lineage due to ancient demonic origins, Kouma stands out for the purity of his Oni blood. Consequently, his family imprisoned him. Later, another Half-Demon family killed his kin, keeping him as a guard dog. Aware of his dangerous impulses, Kouma suppressed them. When Kiri assassinated the head of that family, he burst Kouma's right eye in a frenzy, triggering his "Inversion Impulse" for the first time. This loss of control turned Kouma into the monster he became. During the Nanaya attack, while other attackers were killed by traps or dispatched by Kiri, only Kouma remained unharmed. He killed Kiri but sustained a fatal wound, losing control and massacring the rest of the clan. Shiki's mother shielded him, dying in the process. Whether Kouma died from his injuries or survived remains unknown. This incident made him Shiki's second greatest fear, after Shiki's own "Mystic Eyes of Death Perception".
(Source: Wikipedia, Kagetsu Tohya - Ten Nights of Dreams - "Red Demon God")