How do you get the 2015 LCK Rebels Anarchy?
It was sold in the League of Legends store. Riot's description in the client reads: “This icon was released in the store for purchase during the 2015 esports season.”
Is the 2015 LCK Rebels Anarchy still available?
Probably not. Riot tied the 2015 LCK Rebels Anarchy to 2015 (store purchase), and it does not normally bring back past event rewards or bundles.
