Kami no Tou: Ouji no Kikan

The story begins with a tower that selects some people to climb on it and in return, he will fulfill their desire whatever it will be. Many people get selected and they are known as regulars. A young boy named Bam got randomly selected he is irregular but the tower allows him to get in and he wants to help his friend Rachel with that. In their journey, they met Viole a mysterious and powerful person and he became their member and continued their journey.