Jordan

Vivi is important as a shell for whatever imu is. Whatever imu is, is currently in the ancestor of Vivi and it needs another host. Now whether Luffy beats the current shell of imu and it goes into Vivi after then he has to do it again etc. Under that robe I expect a wizened and decayed body only held together by the powers of imu.

It's. I doubt artificially created but. Ore likely by the "earth god" or it's the serpent of eternalflame, or just some other earth based devil fruit. Races seem to go extinct all the time in the one piece world.