In my current, largely improv, campaign [i've told two stories from it so far and we're only in the first dungeon] i've introduced an npc Kender rogue named Bizlet as a guest party member.
The group, OOC, are barely even aware of what a Kender is, much less so IC. They do suspect he's the reason they have stuff missing from their prologue tavern encounter, but even after allowing them to sift through his kender pouch a bit [poor rolls] they don't manage to pull out their missing stuff [nor can Bizlet... he rolled horribly too xD]
Anyhow, Bizlet got some exceptional stat rolls [Had stats gen'd by 6 x 4d6, drop lowest, assign as desired], two average and one abominable one. [str11 dex18 con13 int18 wis5 cha17] Using the 3.5 dandwiki for Kender, I assigned bonuses from there, leaving his stats [str9 dex20 con 13 int 20 wis3 cha 17]
At first, my plan when I rolled this guy up was he was just going to be a typical kender who becomes dead set on adventuring with my PCs, but then I had a notion. I was going to create a kender-turned-fledgling-god. Bizlet, as a deity, would retain the aloof innocence of the kender race. His presence among the party is more a projection, one that can level up and such as if a level 1 [going forward], of his god form while the actual location of where he is from hasn't revealed itself, even to me.
This projection is going to be killed, by a trap only he can trigger, in an upcoming session and in front of the whole party. No way for them to rescue him from this fate short of some exceptionally lucky dice rolls, mostly due to distance or some such. I'll learn this when the time comes. Anyhow, as best the party is aware, the Bizlet they met and knew, briefly, will be quite dead.
Towards the end of the dungeon, they will meet him again, quite whole. The fact he died won't seem to bother him, to which he'll just respond about how horrible it was and generally treat it as if it wasn't any worse than a skinned knee, at which point he'll keep journeying with them, whether they desire so or not.
His projection won't have any additional power from the deity side aside from the returning from death bit; something I plan to continue to employ, just without making the death a railroaded event. He won't intentionally go sacrificial puppet for the party and will otherwise react entirely normally for a leveling kender until the story manages to connect to his god status somehow. Its an evolving work, so I don't know how it'll go from here beyond the rough plans i've got laid out!