Karthus Skin Concept
This is my first time making up a skin concept so if it's bad forgive me.
So what i was thinking was Tennis Karthus. His q would be a tennis ball that blows up. His w would be a tennis net. His e could have a swirling storm of tennis balls that kill you. His ult i got nothing for. His auto attack would be hitting or throwing tennis balls at the target.