You may want to reread chapters 30 and 31 that covered him. Long story short he's just insane. When he saw Shimoda use his power to make his religious nutjob of a mother jump from a bridge he snapped, declared him his personal god and strove to imitate him in everything, including the flat iron scar and killing his mother (who was a normal, decent human).
Of course, seeing how he shied away from killing here, we could deal with an unreliable narrator (which he has already proven to be in chapter 30 where he claimed Shimoda's backstory to be his own).