This quest is not available in game.
Retrieve the Tablet of Verga for Gan'rul Bloodeye in Orgrimmar.
So few warlocks remain... We risk much, but the risks are warranted. You must quickly reach maturity in your ability if you are to be of use to the Horde and to the Warchief.
It is time that you learned a new summoning spell.
First, you must recover the Tablet of Verga, which was stolen by warlocks of the Burning Blade and is now kept at their lair in Skull Rock to the east of the city. With the tablet, I will show you the runes necessary to summoning a voidwalker.