A while back, years, really, Moseslmpg posted his research into the Devil Trigger Runes in DMC1. Well, my computer crashed and I didn't back them up so does anyone have them? I tried contacting him here but he hasn't responded and the original links are long dead.
PS: Trying to figuere them out myself I found that they might be from the Siddham alphabet, known in Japan as Bonji, which are part of an ancient Indian alphabet, Sanskrit, used to create wards and talismans in esoteric Buddhism. In this case I'd guess these characters would be used to imply exorcism but really Moe would know more than I.
Another game that has similar use of Bonji was the Fatal Frame series where they are inscribed into the camera (camera obscura) to trap ghosts.

PS: Trying to figuere them out myself I found that they might be from the Siddham alphabet, known in Japan as Bonji, which are part of an ancient Indian alphabet, Sanskrit, used to create wards and talismans in esoteric Buddhism. In this case I'd guess these characters would be used to imply exorcism but really Moe would know more than I.
Another game that has similar use of Bonji was the Fatal Frame series where they are inscribed into the camera (camera obscura) to trap ghosts.