When I played OMORI in high school, I think I saw a lot of myself in Basil. Soft spoken, sensitive, and on the edge of a breakdown from carrying self-blame and hatred. I've since become better mentally, but Basil still speaks to a part of myself -- the scared, lonely little girl clinging to small friendships she could find.
To be honest, he's kind of a walking spoiler, so I really can't say much without spoiling the entire plot of OMORI.