"Think about it, you and I, joined in one body. We'll have amazing strength."
Union of Rivals (合体!!ベジータの誇りと悟空の怒り, Gattai!! Bejīta no Hokori to Goku no Ikari) is the fifteenth episode of the Fusion Saga and the two hundred sixty-eighth overall episode in the original dubbed and the uncut Dragon Ball Z series. The episode first aired on June 28, 1995. Its original American air date was November 7, 2002.
The episode begins with Super Buu giving the newly restored Goku, to the count of 5 to find someone to fuse with. Goku has two choices because Tien has been knocked out by Buu. Goku imagines a fusion with Dende, but Goku realizes that that would not be a good idea, because the Earth still needs the Dragon Balls, and Dende does not have any fighting experience. The other choice is Mr. Satan. Goku imagines the fusion with him and says that Mr. Satan is not a warrior but knows basic martial arts, so he makes the decision to fuse with Him. Just as it appears he is going to throw one of the Potara to Mr. Satan, Goku senses someone's ki; that of Vegeta, who has just arrived. Goku uses his Instant Transmission to go to Vegeta and tries to talk him into fusing. Vegeta refuses, saying that he has crushed Vegeta's pride once again by holding back his Super Saiyan 3 transformation in their battle when Vegeta was under Babidi's control. He also says that he would rather die than fuse with Goku.
Goku keeps trying to talk him into fusing when Super Buu shows up and beats up both Goku and Vegeta. Goku is worried that this is the end of them and the Earth, but Vegeta is being still too proud to accept that he needs Goku's help. Goku then he gives a speech about how Vegeta always says he is a Saiyan Prince and that the two of them are the last survivors of the mighty warrior race. In the speech he says that the Saiyans are gone, and that they can start a new race and have a chance to save another planet from the same fate as their home planet. He then tells Vegeta that Bulma has been killed and Trunks has been absorbed by Super Buu, which angers Vegeta that he has lost his family. Vegeta agrees to the fusion because he wants to avenge his family's death. Just as Super Buu is getting ready for another attack, the two fuse. At the end of the episode, a new fusion character is formed, Vegito.
- Goku (Super Saiyan) & Vegeta (Super Saiyan) vs. Super Buu (w/ Gohan Absorbed)
- Instant Transmission - A technique using to travel long distances requiring a familiar ki signal as a source. Used by Goku to teleport to Vegeta when the latter returned to Earth.
- Ultimate Cannon - Attempted twice by Super Buu against Goku and Vegeta: the first is countered by energy spheres from the two Saiyans, and their fusion into Vegito halted Super Buu from firing the second.
- Continuous Energy Bullets - Vegeta uses a Continuous Energy Bullet technique similar to Piccolo's Hellzone Grenade technique which he first used in the fight against Android 17, against Super Buu, but the Majin retaliates with an energy shield.
- Full Nelson - A physical hold where the user holds the victim's arms and upper area, removing their ability to move freely. Used by Super Buu on Vegeta, but the latter was released by Goku.
- Blitzkrieg - Used by Super Buu to attack Goku and Vegeta, but the two Saiyans frantically dodge the beams.
- Combined Energy Wave - Used by Goku and Vegeta to attack Super Buu, but the Majin counters them with his Mystic Shooter.
- Mystic Shooter - A red disk-based energy volley used by Super Buu against Goku and Vegeta, injuring them and reverting them from their Super Saiyan states.
"Wake up! Majin Buu's eaten everyone we care about! Everyone is gone, even Bulma! They've become part of Buu, they can't even die! I just thought the least we could do is put our old differences aside, just this once, and really work together. We owe that to our teammates, our families Vegeta, our friends! Look, you've always talked about our Saiyan race, how we're the last of a mighty people. Well it's time we accept we're starting a new race, one that can be just as strong, just as proud! But not if we're caught up in so much of our old birthrights to see what we have right in front of us! We've lost our old race Vegeta... let's not lose this one, too!"
- This is the third episode where Vegeta shows his love for his family, the first time shown in the episode Cell Returns! and the second time in the episode Final Atonement.
- This is the only episode in the Buu saga the Vegeta's Vision theme is played, it plays when Goku tells Vegeta that Super Buu has killed everyone including Bulma.