Ena, an androgynous shikabane of the Shichisei group, obsessively pursues beauty—a fixation defining his human life and undead existence. As a sculptor, he struggled to capture true beauty until modeling a young boy. When the boy injured himself, marring his appearance, Ena strangled him in rage, perceiving the transition from life to death as beauty's pinnacle. He crafted a display of the corpse in ritual strangulation, working until exhaustion killed him. His obsession then resurrected him as a shikabane, possessing the boy's body to endlessly recreate that fleeting moment by kidnapping and murdering young boys and girls.

Ena's core ability transfers his consciousness between nearby corpses upon bodily damage, granting regeneration beyond conventional weaknesses like brain destruction—a power born from inhabiting a foreign body. He wields a specialized metal ball weapon that grinds targets to dust. Prioritizing his aesthetic obsession over survival, this trait drew Hazama to recruit him into the Shichisei. Within the group, he joined the Hoshimura Clan massacre, directly causing Makina's mortal death to advance his goals.

During the series, Ena possesses Ouri Kagami's body to fatally stab Keisei Tagami. Makina, augmented by Ouri's rune-enhanced regeneration, destroys Ena's metal ball—the physical manifestation of his curse—shattering his regenerative power. Makina delivers the final blow. In death, fragmented memories surface: his suicide after failing to achieve beauty in life, followed by corpse transplantation. These flashbacks reveal the cyclical tragedy of his existence, forever bound to an unattainable ideal.