Dark Dragon Ball is the second chapter of Super Dragon Ball Heroes: Dark Demon Realm Mission.
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, Mechikabura says he will do so and will get revenge on the Supreme Kai of Time. However the Dark Dragon Balls disperse, and the Time Breaker Namekian 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 Chronoa is checking the scrolls and finds that one history has changed, she sends Goku 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 and arrive on Planet Namek, where they find that Frieza has merged with a Dark Dragon Ball and has easily taken down Super Saiyan Goku with just half his power. Frieza prepares to kill Goku (Namek) but is intercepted by Trunks, however Frieza manages to toss him away, Goku (Xeno) steps in and attacks Frieza, but the tyrant recovers and hits Goku (Xeno) away. Super Saiyan Goku (Namek) and Goku (Xeno) then both prepare Super Kamehamehas and fire them Frieza, who responds by taking on his 100% Full Power form, and holds the two Kamehamehas back. However this gives Trunks time to slice him in half, 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. However when Trunks quickly attacks again 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 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
- Goku (Super Saiyan), Future Trunks and Xeno Goku vs. Frieza
- Future Trunks vs. Towa and Mira