In Athas, there are options for high level Psionicist / Clerics or Psionicist / (Defilers | Preservers) to become advanced beings.
Is there such an advancement path for high level Psionicist / Druids?
Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers.Visit Stack Exchange
Role-playing Games Stack Exchange is a question and answer site for gamemasters and players of tabletop, paper-and-pencil role-playing games. It only takes a minute to sign up.Sign up to join this community
Yes, according to the supplement Earth, Air, Fire and Water they can turn into spirits of the land.