Ken Amada is the youngest human member of SEES and one of only two who doesn't go to Gekkoukan High School. He's surprisingly mature for his age, though that maturity sometimes works against him—he can come across as too grown-up, too quick to act beyond what a kid his age should be dealing with. To compensate for his short stature, he fights with long spears. His Personas lean toward support, handling both healing and light-based instant-kill attacks that can end fights in a single hit.
Ken ends up living in the SEES dorm after Ikutsuki invites him in. He's an orphan with nowhere else to go, and once they realize he can wield a Persona, they bring him into the organization proper.
Character designer Shigenori Soejima has mentioned that Ken was deliberately designed with a nostalgic quality rather than trying to match how modern Japanese kids actually look.
Content compiled by AnimeList.moe from publicly available sources.