Because Stephen is exposed to political and formal matters since birth, he talks professionally, even as a kid. This was probably the reason why he was fated to be EVS'ed, but act as a voice for the victims.
Another thing worth noting is that, whenever he re-simulates his transformation from a kid to being an adult, he says that he 'likes' the feeling of it.
Full Name: Stephen Cain
Father’s Occupation: Canadian National living in Enidouka
Mother’s Occupation: Businesswoman
Age: 11 (in story as human), 21 (in story after death/as zeryte)
Birthday: December 1, 1995 (Sagittarius)
Height: 4’10” (11), 6’2” (21)
Powers: ZSP, EVS (Revert-EVS since he’s a Permanent EVS zeryte)
Hobbies: Studying, Watching political news
Greatest Dream: To be a lawyer
Personality: Determined, Professional-like
Related Characters: Olga (mentor and adoptive sister), Rina (childhood friend)
Story: Curse of Growth