[quote=@Nerdy Reference]
Similar to Undead, but not quite. I'm thinking more an Elemental in the vein of Fire or Water, but instead going for an expression of Negative Energy. Undead are not raw Negative Energy, but rather are kept animate by it. I'm thinking she'd be a sort of Shadow Mephit. Hell, maybe that's a better name.
[/quote]

xD everyone is going to end up Fire elemental. Hard to say what "life forms" there are native to a plane who's main feature is death. Only native outsiders that came up when I googled were Drelbs, trillochs, and xeg-yi, and there isnt much info on them. Might have more reference material if you were going more shadow plane stuff.