Yuudai Saejima

Yuudai Saejima (冴島 雄大) was Minoru and Akane's former high school classmate at Sakurazaka Senior High. Following the fall of Japan to Magical Beasts, he became the Vice-Commander of the Knights in the human settlement of Messiah.

Appearance
Yuudai appeared to be a young adult with short black hair and facial hair whilst wearing a black shirt with a necklace under a Sakurazaka Senior High uniform as his Messiah uniform. It should be noted that he was often referred to as a gorilla due his physique and expertise on Judo.

Personality
Not much known about Yuudai's personality when he was a student. However, when Yuudai as a Vice Commander for the Messiah, he was a blunt man who would abuse his position in attempt to be in a relationship with Akane even going as far as to blackmail her to do as he says.

Skills and Abilities
Yuudai was noted to be an expert at Judo as Minoru recalled in his past life that he was the national champion before the magical beasts invaded Japan. He was also a proficient fighter and can use magic though not to the extent as members of the Crimson Order or Shadow Garden.

Akane Nishino
Akane's former classmate, Yuudai often tried to pursue a relationship with her but to no avail. Whenever the two argue or angered, he would often blackmail her under the threat of her remembering her time as the First Knight.

Yuuka
Fellow double-agent for the Alliance, Yuudai was bribed into their side as their mole in the Messiah until Yuuka murdered him after successfully fending off an magical beast invasion.

Akira Nishino
Scientist for the Messiah and Akane's brother, Akira was unaware of either Yuuka and Yuudai's antics until his death.

Minoru Kagenou / The Black Knight
Former classmate of his late incarnation, Minoru was able to recall Yuudai in his past life as he was affectionally referred to as a gorilla and expertise on Judo. When Akane took Minoru in under her care, Yuudai attempted to leave him to eaten by monsters until Akane defended him thus angering him even further out of jealously.

Trivia

 * Yuudai was one of the only known students of Sukurazaka High School before the invasion. The others would be Akane and Minoru.