This is an idea for an ULTIMATE skin for Kindred. As we know, Kindred is like "the Grim Reaper" of Runeterra. It is reasonable to presume then that each of the cultures within Runeterra may have a slightly different perception of how Kindred appears. Spirits of Runeterra Kindred plays off of that idea, as Kindred shifts her appearance over time according to the aesthetic themes of the various locations within the game as she collects her marks. When Kindred kills a champion, she gains essence based on where that champion is from, i.e. Demacia, Noxus, Ionia, etc. If the champion is her mark, she gets double essence. If the champion is not affiliated, the essence could go into a general pool or Kindred could choose what they want to do with it.
Let's say, for example, that in a game Kindred kills Azir, Renekton and/or Nasus. Kindred has the opportunity to take on a more Shuriman appearance. On the other hand, let's say Kindred kills Gangplank, Illaoi, and/or Miss Fortune. Kindred will look more like a resident of Bilgewater. As Kindred kills people, they steal the essence of their victim's home, assimilating to them over the course of the game. In a sense, her final appearance is like a log of their past actions, as it reflects the essence Kindred claimed during the game.
That means every game Kindred will finish looking different. One game you may end with Noxian Kindred and another game you could end with Piltover Kindred. You never know for sure what you will get going in and I think that could be really fun! When you use your ult, as well, the ground will be marked with the symbol of your location as well for the duration of the ult.
Overall, I think this idea would be really fun to play and worthy of the title of an Ultimate skin! I hope you all like the idea too!! Unfortunately, I can't draw, so if anyone wants to draw some things for this idea, be my guest. :)