The naaru in the Warcraft Universe are a race of inter-dimensional, sentient energy beings made up of scintillating holy energies. They are perhaps the purest expression of the Holy Light that exists in the universe, and have vowed to bring peace and hope to all mortal civilizations and waylay the forces of the Void.
In the primordial era following the birth of the universe — a result of the clash between the Light and Void — shards of fractured Light occasionally gathered and formed clouds of Light from which the benevolent naaru appeared.
The titans were more powerful than the average naaru, although outnumbered by them.
The void lords regard the naaru as "beloved brethren that lost the true path."