"Dark Demon God Boo" (暗黒魔神ブウ Ankoku Majin Bū) is the fifth chapter of Super Dragon Ball Heroes: Dark Demon Realm Mission!.
Xeno Goku faces off against Xeno Majin Buu who has merged with the Three-Star Dark Dragon Ball in battle, and is told by Chronoa that she is leaving to call reinformcements. As the Demon Realm Soldiers surround them on all sides, Demon God Dabura descends onto the battlefield and soon attacks Xeno Majin Buu with his objective to steal the Dark Dragon Ball from him. Dabura notes that the version of him from that history would be thankful that he gets to have his way with Xeno Majin Buu, and Xeno Majin Buu grows enraged. Drawing his sword, he slices Xeno Majin Buu in half and turns his attention towards Xeno Goku, proclaiming that he will use his new Demon God power to kill him. Xeno Goku rushes in to attack him and the two exchange blows, Xeno Dabura unleashing a powerful slash that nearly catches Goku. However while Dabura is preoccupied with Xeno Goku, Xeno Majin Buu envelops Dabura from behind and absorbs him, becoming the far stronger Dark Demon God Buu.
The Demon Realm Soldiers rush at the newly formed Xeno Majin Buu to save Dabura, but they along with their ships are quickly eradicated. He turns his attention to Xeno Goku and attacks him, appearing to have the upper hand. Xeno Trunks appears intercepting an overhead strike aimed for Xeno Goku, having been brought to the battlefield by Chronoa along with Xeno Vegeta. Trunks transforms into a Super Saiyan and fights Buu to buy time while Chronoa gives her Potara earrings to Xeno Goku and the reluctant Xeno Vegeta, who fuse into Xeno Vegito.
Xeno Vegito immediately steps in between the battle involving Xeno Majin Buu and Xeno Trunks, breaking Buu's sword and fighting evenly with Dark Demon God Buu. Xeno Vegito fires his Spirit Saber technique directly at Xeno Majin Buu but the attack is blocked by the sudden appearance of Chamel, who proclaims that he will be taking the Dark Dragon Ball.
Meanwhile, in another timeline, Xeno Turles who has merged with the Four-Star Dark Dragon Ball encounters Salsa who has shown up alongside Mechikabura and the Dark-Masked King in order to recover his Dark Dragon Ball.
- Xeno Goku
- Xeno Majin Buu
- Demon Realm Soldier
- Xeno Trunks
- Xeno Vegeta
- Xeno Vegito
- Xeno Turles
- Dark-Masked King
- Xeno Goku vs. Xeno Majin Buu
- Dabura (Demon God) vs. Xeno Majin Buu
- Xeno Goku vs. Dabura (Demon God)
- Xeno Majin Buu (Dark Demon God Buu) vs. Demon Realm Soldiers
- Xeno Goku vs. Xeno Majin Buu (Dark Demon God Buu)
- Xeno Trunks (Base/Super Saiyan) vs. Xeno Majin Buu (Dark Demon God Buu)
- Xeno Vegito vs. Xeno Majin Buu (Dark Demon God)
Game and Manga differences
- The battle against Xeno Majin Buu took place on Earth in the game.
- The Dark Empire forces present for the fight against Xeno Majin Buu included Towa, Mira, Gravy and Putine in the game.
- Xeno Majin Buu was aided by a brainwashed Spopovich, Yamu, Pui Pui and Majin Vegeta in the game.
- Dabura and his soldiers also fight Buu in the game, while in the manga it is only Xeno Goku.
- Xeno Vegito and Chamel only appear in the game.
- The introduction of Xeno Turles happened later in the game, as the Time Patrol also arrived to fight him.
- This chapter and its events are loosely based on the Dark Demon God Buu Saga added in SDBH Mission 4.