I'd go with Outsider for the creature type. Based on your description of where the creatures come from, they're essentially transformed petitioners put into their new existence based on their actions in life. That's where most fiends (evil outsiders) come from in D&D.
I'd say this
is the part of the Outsider description that seems most applicable:
Unlike most other living creatures, an outsider does not have a dual natureóits soul and body form one unit. When an outsider is slain, no soul is set loose. Spells that restore souls to their bodies, such as raise dead, reincarnate, and resurrection, donít work on an outsider. It takes a different magical effect, such as limited wish, wish, miracle, or true resurrection to restore it to life. An outsider with the native subtype can be raised, reincarnated, or resurrected just as other living creatures can be.