Number 39: Utopia, known as Numbers 39: King of Wishes, Hope (
"Utopia" is the only "Number" that is cooperating with Yuma and Astral by its own free will, proven by the fact that it was the only one who did not side with "Number 96". However, its power will corrupt any other Duelist who uses it as the way other "Number" cards do.
He was willing to protect Astral and was very concerned when Yuma was struggling to control "Number C32: Shark Drake Veiss" during Yuma's Duel with Shark. He would come out from the Emperor's Key to assist Yuma whenever he was in trouble.
Number 39's card was the sole "Number" to remain in Astral's possession after his memories were lost, a blank card at the time. During Yuma's Duel with Shark, the blank card took the form of Utopia based on Yuma's desires and became his ace monster.
Utopia became Yuma's favorite "Number", using it in most of his Duels and refers to him more personally than most of his other monsters, as shown when Yuma screams out of frustration when "Utopia" was defeated by "Black Ray Lancer". During Yuma's Duel with Kaze, Roku notices that "Utopia" has a special power. During Yuma's Duel with Fortuno, "Utopia" was given a Chaos form known as "Number C39: Utopia Ray".
While Yuma confronted Dextra and Nistro during the WDC, Number 96 appeared within Emperor's Key to confront Astral. Astral asked if he broke the seal, and Number 96 responded by saying that's what the "Numbers" wanted to begin with. Astral questioned why the other "Numbers" gave their strength to Number 96, who responded once more that it's what all "Numbers" want - the world's destruction. He claimed that Astral also wanted the same. Neither being seemed to notice that although the other numbers' pillars were all glowing, Utopia's remained dark.
Astral denied it, but Number 96 pointed out his very presence as proof against that. He told Astral to remember his mission and join the "Numbers". He assaulted Astral, but was fended off by Utopia, which surprised both of them. Number 96 asked if Utopia meant to stand against them, and concluded that he'll just start by absorbing him first. He then continued his assault via the use of his own card.
Astral realized Yuma needs help so he ordered Utopia to stop protecting him and go help Yuma. Utopia looks at Astral worried, but decides to obey. Number 96 tried to stop him; however Utopia managed to escape and go to Yuma. During the Duel, Yuma and Astral, who managed to defeat Number 96, used "Double or Nothing!" and "Double Tension" with "Utopia", which allowed him to use a new attack they called "Rising Sun Supreme Slash" ("Hope Sword Mars Slash" in the Japan).
He is later summoned when Yuma and Astral enter Hart's consciousness as Vetrix's hatred appears in the form of a dark dragon, causing Hart to be in pain. Utopia battles and slays Vetrix's hatred, causing Vetrix's control over Hart to fade. 
- ↑ 1.0 1.1 1.2 Yu-Gi-Oh! ZEXAL Episode 37: "Double Jeopardy: Part 1"
- ↑ 2.0 2.1 Yu-Gi-Oh! ZEXAL Episode 38: "Double Jeopardy: Part 2"
- ↑ Yu-Gi-Oh! ZEXAL Episode 5: "Flipping Out, Part 1"
- ↑ Yu-Gi-Oh! ZEXAL Episode 6: "Flipping Out, Part 2"
- ↑ Yu-Gi-Oh! ZEXAL Episode 20: "Roots of the Problem"
- ↑ 6.0 6.1 Yu-Gi-Oh! ZEXAL Episode 62: "Duel of Destiny: Part 2"
- ↑ 7.0 7.1 Yu-Gi-Oh! ZEXAL Episode 74: "Attack of the Barians: Part 1"
- ↑ Yu-Gi-Oh! ZEXAL Episode 2: "Go With the Flow, Part 2"
- ↑ Yu-Gi-Oh! ZEXAL Episode 10: "Shark Attack"
- ↑ Yu-Gi-Oh! ZEXAL Episode 16: "Training Days, Part 2"
- ↑ Yu-Gi-Oh! ZEXAL Episode 18: "It's in the Cards, Part 2"
- ↑ Yu-Gi-Oh! ZEXAL Episode 64: "Change of Hart"
- ↑ Yu-Gi-Oh! ZEXAL Episode 111: "A World of Chaos: Part 2"
- ↑ Yu-Gi-Oh! ZEXAL Episode 118: "Mission: Astral World, Part 1"