Aggonar

Aggonar was a pit lord who resided in Outland. When he died, his demonic essence was left behind to corrupt sacred draenei pools into what are now known as Pools of Aggonar. An altar named Altar of Aggonar is also located in these pools. His bones are all that remain, and the demonic eredar Arazzius the Cruel &mdash; master of the Burning Legion in Hellfire Peninsula &mdash; resides within them.

Trivia
The quest claims that Aggonis, a mo'arg felguard, is an offspring of Aggonar, yet it's unknown if he is a direct son or a fel-sworn of another race corrupted by this pit lord.