He is the son of CEO of Beruhern Corp. Soichiro Arahabaki. He has been used for experiments and has been implanted with a Harmonie device allowing him to take complete control over extends. Due to his past life, he has a strong hatred against the people responsible for experimenting and hurting children. Tetsurou has a noble heart and always has good intentions but tends to make bashful decisions that cause trouble for himself and others.