The new Yorick Undertaker skin is just..

And the splash art fits with the previously released Scourge, Inquisitor, and Revenant skins http://vignette1.wikia.nocookie.net/leagueoflegends/images/0/0c/Kayle_IronInquisitorSkin.jpg/revision/latest?cb=20160425233946

I am not sure (but pretty confident), but his Splash Art might be a reference to Bloodborne, more specifically to Father Cascoigne, that's the first thing I thought of when i saw it. The same way Scourge, Inquisitor and Revenant skins are a reference to when Dark Souls 3 was released. The two games are from the same company (From Software) and I recommend them.

At 0:14 you can start seeing the resemblance:

https://www.youtube.com/watch?v=XS4aNi3bLD4