Gabaras commands the Black Banner Army as its absolute leader, serving as the narrative's primary antagonist. His faction actively seeks to overthrow the Kingdom of Evermore. His central objective is eliminating Princess Astrid, the parallel-world counterpart of Kotona Takashina, whose life force exists simultaneously across both dimensions.

Gabaras initiates the core conflict by deploying assassins into the human world to target Kotona, resulting in her near-fatal stabbing with a cursed dagger. This interdimensional attack forces protagonists Yū and Haru into the parallel world to protect both versions of their friend. Gabaras personally directs military operations against Evermore, positioning himself as the existential threat to the kingdom's stability.

His strategic significance stems from creating the central dilemma: because Kotona and Princess Astrid share a life force across worlds, any harm to either endangers both, forcing the protagonists to confront impossible choices regarding their friend's survival. Gabaras functions narratively as the catalyst for the protagonists' interdimensional journey and their subsequent moral challenges. His persistent campaigns against Evermore drive the primary conflict throughout the story.