Whilst there's no mention of his being a Sonderkommando in the film, he was at a concentration camp. I was actually thinking that any Silent Hill crossover I might attempt would have to be written mainly from the point of view of Charles trying to find Erik and be quite vague about what Erik actually experiences, both because I want to avoid any glaring inaccuracies when writing about something so serious and because I don't want to feel I'm exploiting real human tragedy for the sake of fanfiction.

Alternatively, Erik's Silent Hill could deal mainly with his future rather than his past: his quest for revenge and the possibility that he might eventually become the person he's trying to take revenge on.