Sky is an element of Card Wars played by Alice. The following cards are her deck.

Card 1-Rainbow Vortex: Swallows other player's land

Card 2-Star Gazer: Reveals other player's cards

Card 3-Lightning Queen: Attacks other player with lightning bolts

Card 4-Rain Cloud: Just....rain

Card 5-Energy Cat: Steals other player's energy

Card 6-Regaining Source of Silence: Player may charge cards/characters to gain power without being disturbed/attacked

Card 7-Death Storm: Automaticly kills card/character

Card 8-Mystery Card: unknown

Card 9-Heat Wave: Destroys other player's deck/land therefor wins the game

Card 10-The Blizzard Cometh: Switches card deck with other player

Though these are not shown in the series yet