Summoned Old God

While the orcish Horde massed under Gul'dan, the arakkoa sought to defend themselves from the threat by striking against him. Gul'dan learned of their intentions and cast a mighty spell that destroyed their camps and twisted their spirits.

The spirits of the dark conclave sought to summon an ancient and powerful evil through a ritual conducted at the lava pits to the south of the Sketh'lon Base Camp. Gul'dan's magic mingled with their own, empowering them to aid this creature in manifesting in Outland. If they were successful, the death and destruction it would bring would have been unimaginable.

The creature is known as the Summoned Old God. It uses the same model as the Old God C'thun.

At an unknown point in time, the arakkoa turned away from the veneration of Rukhmar. The arakkoa came to worship a new master, one who promised them untold power and status in the cosmos. The Sethekk believe themselves to be the true and most loyal followers of this being. The Sethekk (incorrectly) interpreted destruction of Auchindoun to be the arrival of their master on Draenor. This Old God is that master, and it is not one of the ones trapped on Azeroth.

The Black Blood of Draenor may be related to it, similar the Yogg-Saron and the Black Blood of Yogg-Saron or the Entropic Oozes. Oozes may be related to the Old Gods.