Many universe have alternate realitys where time is different and society as well. Well, Dark Reality universe Zero is by far among the most twisted alternate realities of all. In this universe 26th century started off with the disocovery of Sarci Nevron, however in this reality was the by product of natural evoultion and not created by Rathal. In this Universe their is no Rathal. Sarci Nevron and Korra both had timelines that intercrossed each other especially since by the nend of the Corporate War Sarci Nevron Had conquered the galaxy. By the late 27th century he had conquered the Universe.
Korra meanwhile had been succefully mutate and her creator had lived allowing her master to establish a massive species coalition.
Sarci allowed korra's species to control many worlds in the Universe in exchange for Korra to be his wife.
Around the late 29th century, Korra and Sarci of this universe had a clash with the Firestorm of the Prime universe.
More detail will come in time.