Ken Amada is the youngest human member of SEES, and one of the two who don't attend Gekkoukan High School. He is mature, but sometimes he is too precocious for his own good. He uses long spears to make up for his short stature. His Personas can be used for healing, and to cast light-based spells that occasionally instantly kill the enemy. Ken is invited by Ikutsuki to live in the SEES dorm because he is an orphan with no home to return to. He is revealed to have the potential to wield Persona and is asked to join the organization.

According to character designer Shigenori Soejima, Ken was designed to have a nostalgic look, rather than to reflect the style of modern Japanese children.