>>88974785Lore-wise, and completely sincerely, it's because there's a cult in Silent Hill (that is partially the reason why SH is so fucked) which has cult uniforms for various tasks. The Triangle Helmet was actually a red hood worn by these cult members, made uncomfortable intentionally by the cult members to prevent complacency in their tasks while wearing it. The Executioner Outfit was similar, wearing just a red hood and thick waist apron bearing a resemblance to a butcher. These outfits were actually used by the cult members to execute criminals AND do ceremonial sacrifices before (and during the time) they went into hiding.
This history led to nursery rhymes and paintings to be made of the cult members, creating the painting of the Executioner James sees in the Historical Society during his trip with Mary to Silent Hill. It had a huge impact on him (with the victims of the Executioner being strung up behind him resulting in bosses like Flesh Lips and the Final Boss) resulting in Pyramid Head being born (with a metal head).
Pyramid Head himself is the result of James feeling guilty
over killing someone.
This is why you suddenly see a second Pyramid Head near the end of the game, as you just killed Eddie It's also confirmed by the writer himself that if James didn't see the painting, PH would've never been able to "manifest".
>tl;drCult members wore a red hood intentionally made to be uncomfortable for ceremonial purposes.
James saw the paintings of these cult members, particularly of the Executioner outfit, and had it impressed on him.
When SH went to shit, PH was made as a way for James to condemn himself.