An elemental is a mythological being that first appeared in the alchemical works of Paracelsus, a 15th century Swiss scientist. Traditionally, there are four types: gnomes (Earth Elementals); undines (Water Elementals); sylphs, (Air Elementals); and salamanders, (Fire Elementals). In the UO universe, there are several more elemental types: Acid, Blood, Crystal, Ice, Snow, etc. Several creatures related to the elemental group do not sport the 'elemental' sobriquet, namely the Efreet, Kaze Kemono, Rai-Ju, and Sand Vortex.

As a group, elementals are vulnerable to the Elemental Slayer, while specific elemental types are susceptible to certain Lesser Slayers, as well.