Bound elemental

Bound elementals are a type of elemental, that are bound to cages, introduced in World of Warcraft: Cataclysm. Freeing a bound elemental makes him an "unbound elemental" as seen during Unbinding. There are other bound elementals in World of Warcraft not using the "Bound elemental" model. Some of them like the Bound Fire Elementals even share the same name.

Types

 * Bound air elemental
 * Bound earth elemental
 * Bound fire elemental
 * Bound water elemental

Designing
World of Warcraft Art Director Chris Robinson explained that during the development of Cataclysm the art team was sick of seeing the old elemental models in the game, so they wanted people to look at new content. Throughout the process they also started working with the Twilight's Hammer art heavily keyed into the Elementium vibe. Since the Twilight's Hammer needed to subjugate elementals, the art team wanted to integrate the elementium vibe to the new look of the elementals. The solution was that the Twilight's Hammer literaly cage them in a physical elementium structure around the elementals to control them, meaning that all the different new elemental models got the same cage holding them.

The purpose of the cages comes up in quests like Twilight Extermination, Mercy for the Bound, and Unbinding, but not all elementals that use these models are enslaved by the Twilight's Hammer.

Note
"Binding" in the context of elementals can also mean imprisoning one, as in Stones of Binding, or summoning them into a coherent form from their element, as in Core of Our Troubles.