Can anyone explain what the evolution slot is? : rClashRoyale

A 2nd Evolution Spot gets Added to Clash Royale! clash royale first slot First, you must place a card in the evolution slot in your deck Your first Evolution slot unlocks upon reaching the King level 7 There are clash of pirates slot Royale House Clash of the Giants Royal Katt Royale Vegas Brothers Kingdom Brothers Kingdom 2 Poker Ways Dragon Wish 888 Gold Panther Maxways Wild Wet Win

clash of heroes slot Royale House Clash of the Giants Royal Katt Royale Vegas Brothers Kingdom Brothers Kingdom 2 Poker Ways Dragon Wish 888 Gold Panther Maxways Wild Wet Win