Super Dragon Ball Heroes: Ankoku Makai Mission!

After defeating Cell in his timeline, Future Trunks becomes a Time Patroller and partners with Chronoa to face the Time Breakers, later identified as the Dark Empire Forces from the Demon Realm. The Dark Empire revives their leader, Mechikabura, and seeks to recover the scattered Dark Dragon Balls to restore him to his prime. These balls have fused with past villains, granting them increased power. Future Trunks, alongside allies like Goku and Vegeta, works to prevent the Dark Empire's plans from succeeding.