Akaso Eiji is a Japanese actor and model, known for playing Ryuga Banjou in Kamen Rider Build. He is currently represented by Tristone Entertainment.

He belonged to the Nagoya model office "FORM JAPAN" when he was in his teens. He was active as a model and talent under the name Mamoru Akaso (赤楚 衛, Akaso Mamoru). In 2010, he joined the local idol group "BOYS AND MEN" in Nagoya, working on stage performances and regular appearances of variety shows. Eiji is said to have left "BOYS AND MEN" in 2011. Originally, he entered the entertainment agency because he wanted to be an actor and not an idol.

He won the Grand Prix at the men's model audition of Samantha Thavasa in 2013, which became the turning point for him to audition in Tokyo at the age of 19. The trigger that lead Eiji to drop out of university and to enter the world of entertainment was a call from the CEO of his current agency in 2014. In 2015, he transferred to his current agency Tristone Entertainment, working as an actor and starring in television dramas and films in his current stage name