Curate, connect, and discover
Because it's spooky month, Demons AU where Reigen is a rather low level demon who finds himself summoned by a 10 year old Shigeo who's scared of his own powers (still psychic or something else?) and ends up contracted to the kid, maybe at first annoyed a child is who he ended up forming a contract with but over time ends up really caring and protective of this child.
Maybe Shigeo just wanted someone to talk to and there really aren't many beings in this world who could understand what he's looking for or that he could talk to so demon summoning is totally the logical choice here. Shigeo could absolutely destroy Reigen is he wanted even as a kid but nah he just wanted help :')