The Ruins of Solarum

It appears in the alternative timeline the Black Sun.

History
After the worshippers of the Black Sun have been dealt with in the Divine era, they are reduced to but a former sliver of their own glory. With the fall of the last ritualists remains the fight to the very idol the Osprix have worshipped: the Voidspawn of the Solarum god, Rah'yeh.

Rah'yeh himself burns with rage and despair, as he unleashes his mighty dark magics on the Traveler. He is however defeated in the duel, and his fall puts an end on the Black Wing cult.