The in-battle resource used to deploy cards. Regenerates over time during a match; players start at 5 and can hold up to 10 (double/triple Elixir modes speed regeneration).
Battle-only resource; not stored between matches. Distinct from the collectible 'Magic Coin/Elixir' shop items sometimes grouped under Magic Items.
One Elixir every 2.8 seconds in normal time, 1.4 seconds in Double Elixir (the last minute of regulation and most of overtime), and faster still in Triple Elixir modes. Those numbers are why cheap cycle decks exist: they can out-rotate you to a key card.
Answering a push with less Elixir than your opponent spent — say, a 3-cost Skeleton Army eating a 5-cost Prince. Stack enough of those small trades and your counter-push arrives against a player who can't afford an answer. It's the closest thing the game has to a first principle.