Character classes available in Promise of Power represent a broad but shallow sampling of the hundreds presented in the RPG series. There are three proto-classes from among which players can select at the outset of the game: Mercenary, Psionic, and Magic User. Upon reaching fourth level, players may choose a specialization such as Borg, Burster, or Ley Line Walker, some of which are restricted based on proto-class. One character class specially designed for the game – the Elemental Fusionist – was adapted into the Rifts Ultimate Edition core rulebook.