Slapshot Tryndamere for that Canadian hockey spirit.
Replace his sword with a hockey stick, switch his horned helment for a red hockey one, give him a white jersey with a red maple leaf on it, change his movement animations to be smoother, a more fluid skating motion, essentially, and maybe take the Arcade Sona route of actually changing the kill/death interface. It could shout out "Goaaaaaaaaaal!" (or "Enemy Goaaaaaaaaaal!") upon kills and deaths, and could signal the end of a game with a buzzer noise like you would get at any professional hockey game.
Dialogue replaced with horrible hockey puns and poorly-done Canadian-isms is optional, but Riot would probably go for it.