As for phantasms, always imagined those as more of a snapshot, an after-image or something like that. Will-O-the-Wisps are usually either fey or minor negative energy manifestations... IMO...
Necromancy for me deals with the undead, which includes incorporeal undead as well... and manipulation of life and death. Just don't get the right vibe of Kirai [shrugs].
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But yeh, lack of asian mythology knowledge... Most familiar with more western stuff and imaginary lore, like old WoD, DnD (Ravenloft), Warhammer Fantasy RPG and more obscure ones that are not well known outside of sweden.