I don't even think Pyramid Head has an actualy story behind it. In Silent 언덕, 힐 2, it is a voilent monster, which betrays James' 'other half' 또는 something?
In Silent Hill: Homecoming, he acts as a judge 또는 some sorts. If a person 'deserves to die' (in his eyes), it'll hunt down that person and kill him.
And as for the helmet... PH's creators wanted a 'humanlike' monster with a mask on. But then they realized it would be nothing 더 많이 then a man wearing a mask. They decided to give PH a 헬멧 shaped 더 많이 like a triangle, to make it look 더 많이 disturbing. With sharp edges, etc etc, to hurt PH itself wearing it. Once 당신 wear the helmet, 당신 can't take it off, and your a Pyramid Head.