Yuuka

Yuka is a physician of Messiah and secretly, a spy of the Alliance.

Personality
Yuka was once a happy woman until the death of her husband due to Arcadia's fall radically changed her. In present, she was a cruel and vengeful woman. Yuka would manipulate, undermine and murder anyone to accomplish her goals. While undercover as Messiah's physician, she presented herself as a kind and concern woman.

Revenge against the Nishino Family
Years later, Yuka joined a group called the Alliance who tasked her to infiltrate Messiah and sabotaged the group so that they could claim their base as their own. Having successfully infiltrated Messiah, Yuka learned to her outrage that not only Akira Nishino was still conducting his experiments but Akane Nishino had forgotten what happened to Arcadia. Yuka spent her time getting close to Akane all the while secretly planning her revenge against her.

Akane returned from a mission and brought back two survivors of a Magical Beast nest.

Death
Having escaped Messiah, Yuka returned to the spot where she had kept the unconscious Akane Nishino. Suddenly, she was confronted by Minoru who deduced her as the Alliance spy. Yuka explained her past and intentions to Minoru before injecting Akane with the Brute's blood. With Akane now transformed into her First Knight state, Yuka allowed herself to be killed at the First Knight's hands. Despite nearing her end, Yuka hugged the First Knight before laughing, having finally gotten her revenge.