Speak with Lord Arkkoroc in Azshara. Begin your search at the waters edge to find the Temple of Arkkoran.
Part 6 of 9 in this series
There is only one way to harm the demon lord and his minions. A weapon of power must be forged bearing his true name. When such a weapon is forged, the demon and all under his command are vulnerable. A lesser deity resides in Azshara: Lord Arkkoroc. You must seek him out but be warned, his minions will stop at nothing to destroy you if you are discovered. Undoubtedly, you will have to pay a price for such information.
A demon lord? <Lord Arkkoroc laughs.> Perhaps the one can assist you with this information; but first, you must assist the one.
!?