Codex: Card-Time Strategy is a customizable, non-collectable card game set in the Fantasy Strike universe that's inspired by real-time strategy video games such as Starcraft and Warcraft 3. Players each control three different heroes and have access to a tech tree that allows them to use different strategies each time they play.

The goal of the game is to destroy the opponent's base. To do this, players build up an army of units and heroes. Players determine the exact composition of their armies as they play by adding cards to their deck based on the tech they've chosen to pursue.