Thanks for the compliment. I was trying to think of various equivalents to perilium in different games and stories--does anyone have any suggestions? Warhammer has warpstone, there's a video game called Torchlight where the mystical material is ember. Shadows of Brimstone's thing is dark stone. The Superman myth has kryptonite--not too similar except I think it comes in various flavors. Final Fantasy has materia (or immateria in the Kingdom of Loathing). And the philosopher's stone, I suppose. Anything else?