The Great Villainess Strategy of Lily is a turn-based tactics game about Duchess Scarlet, who is accused of regicide. Accused of murdering the Emperor, she forms an alliance with Lily, captain of the airship Stream. Together, they declare war on the Empire, becoming the first military Streamers on the continent. The conflict escalates as impulsiveness and cold pragmatism clash. The player must achieve victory by either capturing all enemy commanders to reveal the truth, or executing the opposition to become the Demon Queen. The outcome of The Great Villainess: Strategy of Lily depends on the fate of the enemy commanders, and defeat occurs when Scarlet or Lily is neutralized.