What is Eredar in World of Warcraft?

Answer 1

They are a non-playable race with an affinity for magic. They are part of the Burning Legion. As for Biology:

"The Eredar mutated by Sargeras's demonic power are physically similar to their original shape, with a few minor differences (the original Eredar shape is thought to have been preserved in the draenei). This creatures are of impressive size, far larger than any human or orc, with a bulky muscular body and a long tail. Long pointed ears sweep back from its bestial face and horns sprout from its wide brow (Although Archimonde's cinematic and drawn art shows a different style of cheek spikes, and no spikes above the eyes). The hooves of demonic eredar are more compact than those of draenei, and most of the demonic breed lacks cranial hair. The hands of demonic eredar are clawed. Most significantly, demonic eredar are much larger than draenei - though few could match Archimonde's preferred height."

Sorry about the block of text.