We knew it wouldn't be easy, but nobody told us how much cardio would be involved when we got into the demon slaying game.

Fortunately, that painful, sweaty realization led us to develop this tumbler as an essential part of every slayer's arsenal.

With a design featuring Inosuke, Zenitsu, Tanjiro and Nezuko, it's the perfect gift for fans of Demon Slayer who know that the only thing worse than a demon is a poorly timed calf cramp.