thames lines for a rambunctious (and only slightly murderous) hp-style poltergeist! he's been kicking around since the mid-1200s so there's lots of room for path crossing. anyone whose life he's made difficult at any point, someone(s) who purposely employed him to make specific lives difficult, reapers to be buds with since he can't die, others to get into trouble with, i'd love another creature also masquerading as a teacher who knows exactly what his deal is, anyone living in the same building who is occasionally disturbed by more traditional poltergeist-y events when he can't get his emotions in check, maybe one or two whose cities or towns were entirely wiped off the map back when he was a whole lot more volatile and are still kind of bitter over the whole thing, honestly everything