Elemental affinity describes what branch of particle manipulation a character is most naturally adept in due to their temperament.
Spriggats have an unusually strong elemental affinity that literally colors their appearance.
Telepath RPG: Servants of GodEdit
The Hero in Telepath RPG: Servants of God is the only character in the series whose elemental affinity may vary depending on the player's choices. The player is given the opportunity to select an elemental affinity for the hero after the completion of the bandit cave mission early on in the game simply by talking to the Nameless One and answering an abstractly-worded question.