Dark Dragon Ball is the second chapter of Super Dragon Ball Heroes: Dark Demon Realm Mission!.
Using the energy that they had gathered from strong warriors, Towa revives Mechikabura in the Demon Realm. However, Mechikabura is weak due to his old age and so Towa tells him to use the Dark Dragon Balls to restore his youth, to which Mechikabura says he will do so and then get his revenge on the Supreme Kai of Time. However the Dark Dragon Balls disperse, and Time Breaker Dende who created them explains that they must first be collected. Towa apologizes to Mechikabura, but he states it's fine and that he has already found one, he grants Towa the power of a Demon God and she heads with Mira to collect the Dark Dragon Ball.
Meanwhile, at the Time Nest, the Supreme Kai of Time Chronoa is checking the scrolls and finds that one history has changed. She is greeted by Goku: Xeno and Future Trunks who say it's been six months since they last saw her but Chronoa tells them that she changed the flow of time in the room they were training in and they haven't even been away three days. She sends Goku: Xeno and Future Trunks to deal with it, and does not come along, as she has been overworking herself, allowing them to train in changed time and checking scrolls.
Trunks and Goku travel back in time to Age 762 and arrive on Planet Namek, where they find that Frieza: Xeno has merged with a Dark Dragon Ball and grown several times more powerful than before and has now easily taken down Super Saiyan Goku. Frieza prepares to kill Goku but is intercepted by Trunks, however the attack has no effect and Frieza manages to toss him away. Goku: Xeno steps in and attacks Frieza: Xeno, but the tyrant recovers and hits Goku; Xeno backwards. Super Saiyan Goku stands up once more, not really sure of why there is another version of himself there and along with Goku: Xeno they both prepare Super Kamehamehas and fire them at Frieza, who responds by taking on his 100% Full Power form, holding the two Kamehamehas back with his hands. However, this gives Trunks an opening and slices him in half from behind, detaching the Dark Dragon Ball from him and changing history back to normal.
Demon God Towa and Mira appear and Towa picks up the Dark Dragon Ball, Trunks attacks but is easily taken down by Towa's new found might. However, when Towa and Mira attempt to leave once more, Trunks quickly attacks again and Mira gets in the way of the attack, sacrificing himself and angering Towa at his death. Towa retreats with the Dark Dragon Ball and the battle between Super Saiyan Goku and 100% Full Power Frieza goes on as it should. Goku and Future Trunks head back to the Time Nest.
Towa arrives back in the Demon Realm to give Mechikabura the Dark Dragon Ball, who reveals that he has summoned multiple Demon Gods to aid in the collection of the balls.
- Goku (Super Saiyan) vs. Frieza: Xeno (Final Form)
- Goku (Super Saiyan), Future Trunks and Goku: Xeno vs. Frieza: Xeno (Final Form/100% Full Power)
- Future Trunks vs. Towa (Demon God) and Mira
Game and Manga differences
- The revival of Mechikabura is shown to be through stolen energy, while in the game it is not, seemingly implied to be through the Dark Dragon Balls.
- It is revealed that a Time Breaker Namekian created these versions of the Dragon Balls, something not shown in the game.
- The fight between the Dark Empire and the Time Patrol is much shorter and greatly differs from the game as well, as Trunks is the only one to ever fight the Empire, Towa and Mira are the only people to fight him, Mira is killed by Trunks, and Towa immediately retreats soon after.
- This chapter and it's events are loosely based on the first Super Dragon Ball Heroes opening.