Kassadin's "Pre-Void" skin isn't accurate anymore!
With the update to Kassadin's lore that come with Kai'sa, his "Pre-Void" skin is a little outdated now. He no longer is corrupted by the Void, he just has many magical artifacts that he is using to seek revenge. I think the easiest fix would just be to switch the Pre-Void Kassadin skin to something like "Young Kassadin." They could even go one step further to tie it into the lore and just call it "Wanderer" or "Adventurer" Kassadin, since it would be from the days he spent being a guide in the Shuriman deserts. And as was suggested by one of the Riot support team members, Tank, this might require a splash update, since the current splash has Void tentacles trying to drag him into the Void. I know I'm pretty late on this since Kai'sa has been out for a while now, but as a lore lover I think it'd be better to try to unify the in-game content this way!