"Battle for the Universe" (全宇宙を賭けた試合 Zen’uchū o Kaketa Shiai, lit. "A Match with the Whole Universe at Stake") is the three hundred fifteenth chapter of Dragon Ball Z and the five hundred ninth overall chapter of the Dragon Ball manga.
As Goku continues to mourn over the loss of his sons and friends on the Sacred World of the Kai, Vegeta blames Goku for his their sons and Piccolo's deaths, as Kibito Kai and Old Kai look into Old Kai's Crystal Ball to find out what has happened to Boo and the Earth. Old Kai manages to find out that not only were all of Goku's friends killed, but the whole entire planet Earth has been destroyed, nothing left but tiny atoms, with not even Boo in sight.
Mr. Satan jokes that Old Kai is just a crazy old man, denying the truth, to which Dende angrily replies that Mr. Satan should respect a Kai, and should bow down. Dende explains to Mr. Satan who Old Kai is, and that he is higher than Kami-sama, and Kaio-sama, who are the lords of worlds. Above them stands the Great Lord of Worlds, and above them stands the Lord of Lords, Kaio-Shin, a.k.a, Old Kai. Mr. Satan stands on in confusion, not understanding a word Dende said to him. Mr. Satan explains his disbelief by stating if Old Kai is a god, why can he not destroy Boo. Old Kai whispers how unlikable he finds the "Champion of the World". Mr. Satan assumes this is all a dream, as he states that nobody is stronger than him, and that soon he will wake up happy and just the way it was before. Mr. Satan even believes since this is a dream, he can do anything he wants, even fly, as Goku and Vegeta look towards him with embarrassment. As Mr. Satan runs towards a cliff, he raises his fist proudly and states he will destroy the evil Boo for destroying his daughter Videl in his dream, and for ruining everything else. As Mr. Satan jumps from the cliff, performing a pose, he falls embarrassingly to the ground, confused as to why he can get hurt in a dream.
Vegeta continues to scold Goku for his decision to save this man at all, as all Goku can do is look on in shock at Mr. Satan's behavior. Vegeta states there is now no more hope due to the Dragon Balls on Earth being destroyed, and all there is left to do is fight to make sure Boo does not destroy Other World. Startled by the news, Old Kai demands to know why there are Dragon Balls on Earth, as he states Namekians are their creators, and thus, only Namekians should have them, calling the Dragon Balls "Cheat Codes." Remembering about the Dragon Balls on Namek, Dende suddenly hatches a plan for everyone to use the Namekian Dragon Balls to revive everyone on the Earth. Suddenly there is hope, as even Vegeta cracks a smile at the news. However, Goku has doubts, as he states Namek is far away from their location, and he doubts his Instant Transmission will be enough. Kibito Kai however states his teleportation abilities can take him to any planet, and now Goku starts to cheer. Old Kai however, refuses for them to use the Dragon Balls, stating the Cosmic Order will fall into chaos. Goku tries to persuade Old Kai into letting them use the Dragon Balls, but Old Kai still refuses bluntly. Goku however, remembers Old Kai's perverted hobbies, and says he will get Old Kai a naked picture of Bulma, Vegeta's wife. Goku states that while Bulma is not young anymore, she still has looks that he knows Old Kai will enjoy. Old Kai starts to change his mind at this offer, and eventually gives into Goku's deal, telling Goku he's always "preferred the more mature ones". Vegeta overhears this deal and manages to figure out that Goku is talking about Bulma, which drives him furious, shouting into Goku's ear asking why he can not give Old Kai a picture of Chi-Chi instead. Goku replies that if he asked her, she would kill him, and that she's "quite flat chested" compared to Bulma. Kibito Kai returns to the Crystal Ball and finds that Boo has finally regenerated after the explosion, and is now loose in space. Old Kai orders Kibito Kai to give Goku and Vegeta is Potara Earrings so they can fuse again, however, even Goku refuses this time around, stating he would rather fight Boo as himself, having a strong feeling his Super Saiyan 3 form will be enough. Vegeta agrees, and congratulates Goku on his decision, finally calling him "A True Saiyan". This news, however, completely shocks Kibito Kai and Old Kai, unable to speak at their decision.
Still in space, Boo manages to locate Goku and Vegeta's energy, and teleports to their location right beside them, giving them all quite a shock and surprise, as Goku states Boo must have learned that ability after seeing Kibito Kai use it. Goku and Vegeta stand their ground, as Goku orders Kibito Kai to teleport everyone else to safety, and that he and Vegeta will combat Boo. As Kibito Kai teleports Dende, and Old Kai to a distant planet, Old Kai looks through his Crystal Ball and starts to boil up over the Saiyans decision not to use the Fusion Dance. Vegeta and Goku discuss who should fight first, so they end up playing Rock-Paper-Scissors to see who gets to battle Boo first. Goku ends up winning, causing Vegeta to walk to the sidelines and wait for his turn, which Goku states he will probably not get. Goku states his disappointment over the events that have occurred the past few days, with Gotenks not being able to destroy Innocent Buu, but Goku realizes quickly Vegeta is not listening. As Goku turns back to his enemy, he notices Boo is sound asleep on the spot, snoring loudly. Goku is insulted by Boo's lack of interest in his opponents, and transforms into a Super Saiyan 3, waking up Boo and beginning the battle for the universe.
- Old Kai states that if the Dragon Balls are used too much, the cosmic order will collapse. While this event does not occur in the manga, in the anime only sequel Dragon Ball GT, when Goku and his friends use the Dragon Balls far too often, the evil Shadow Dragons are born, who plunge the world into chaos, and become the strongest opponents Goku ever faces, with enough power to destroy the entire universe.