Riven's new lore without the league.

Now there is no institute of war to display her "Strength" in order to show the world the true form of Noxian beliefs. So what is there for Riven?

It would be interesting to see her stay on Ionia, as a wandering vigilante/hero/savior, to undo the wrongs she had done during the war, meeting various Ionian characters and honing her "Ki" for her abilities.

It would also allow us to see Yasou hunting her, all the while evading assassins who are after him.