Characters who originate on the inner planes often have completely different origins than those from the material plane. Seriously, every single elemental and genie is itself immortal. Every single mephit is also potentially immortal. So backgrounds for mortals from the war-torn material plane don't necessarily fit immortals from the war-ravaged inner planes. Still, many do. The elemental planes have Fallen Nations, some of which even had Royalty, and whose supporters sometimes form a Resistance. They have Apprentices and masters. They have War, and the wars produce Profiteers and Veterans and Refugees. And, of course, complete Amnesia is as common an occurance on the inner planes as it is on the material. But there are also a bunch of things they can do that people from the material plane