Entropius

Entropius is a void god into which the naaru M'uru transforms during the fifth boss encounter of the Sunwell Plateau. Some parts of M'uru's form are still visible.

Note
This appears to be the "void" that the naaru transform into upon death. Although the other darkened naaru (K'ure and D'ore) have not become void beings, this might be the result of M'uru being drained by the Blood Knights.

Inspiration

 * The name "entropius" is likely a derivation of "entropy", the amount of energy unavailable to perform work on a system, commonly construed to mean the level of "disorder" or "chaos" in a system. Entropy is also defined as the state in which all object are moving toward a higher level of disorder.