Character name: Ciaphas Cain Character age: Physically in his 30's, but his actual age is somewhere over 100.
Places someone might find the character? Things they might be doing? Cain lives in the shelter and enjoys those accommodations, but in the early mornings he does his training exercises, which is everything from running laps to doing sword practice to marksmanship. If he's not teaching a class that day, or on patrol, he'll be found in the club or trying to locate some entertainment for himself that won't get him collared.
Is the character in any IC group, including the school? Details! He's a teacher at the school, and a member of the Defense Force. I think that covers it...
What kind of person does the character get along with? Cain will force himself to get along with almost anyone, since he's so used to having to do that kind of thing to survive. However, people who are real friendship material should possess a good sense of humor and not take themselves too seriously. Enjoying a game of cards or chess is a plus.
Is there any type of CR you feel the character is missing (e.g. romantic interests, mentor figures, etc)? He needs more buddies that he can talk/hang out/gamble with(of either gender). And I would not shun possible romantic interests, though I warn you that Cain is pretty exclusively straight AND he isn't into intense committed relationships. He's a charmer and a gentleman and all too willing to please his partners and stay on good terms with them, but he isn't the sort to settle down.
Other notes? He comes from a GRIMDARK FUTURE where psykers/witches/aliens/mutants are officially the enemy. That, and humans are functionally much more violent and brutal than regimes of the past. This doesn't really make him a bad or brutal person socially, but his perceptions are colored by where he comes from and sometimes that boils to the surface. Basically, be prepared for active but polite distrust.