Flash, Trixie, and Shining Armor rally together to stop the Negative Ten once and for all. But Flash is soon faced with a situation that forces him to potentially make the ultimate sacrifice.
- Adaptational Badass: Due to Flash's Ultimatrix being made from a combination of the Omnitrix's frame and the core of Shadow's Ultimatrix, it maintains all the original Omnitrix's features; something that was a flaw in Ben's version of the Ultimatrixnote .
- Bad Boss: Shadow continues to be this to the rest of the Negative Ten. He completely ignores their advice to him and tells them all to stay out of the fight with the heroes, saying he can beat the three of them on his own. Then after he's beaten, he tries to overload the Plumber Base's power core and destroy the city, not caring about how the rest of his team will die in the blast too.
- Be Careful What You Wish For: Shadow orders the rest of the Negative Ten to stay out of his fight with Flash, Trixie, and Shining, telling them no matter what to not help him. When he finds himself on the losing side of the battle after his Ultimatrix runs out of power, he tries to get the others to help him, only for them to not move a muscle and Devious to throw his orders back in his face with a smirk.Devious: No matter what happens, none of you are to interfere with this fight. Even if things look like they're going bad, stay out of this. Weren't those your Exact Words?
- Bookends: The last alien Flash uses in the story is Volt-Edge, the first alien he ever used.
- Curb-Stomp Battle: Ultimate Volt-Edge easily wipes the floor with the seven remaining members of the Negative Ten.
- Discard and Draw: Flash sacrifices the Omnitrix's core to save the city, but shortly afterwards replaces it with Shadow's Ultimatrix core, essentially replacing the Omnitrix with the Ultimatrix.
- Do Not Adjust Your Set: When Shadow prepares to fight Flash, Trixie, and Shining, he has several drones appear to broadcast the fight all across Canterlot, just so everyone can watch him beat the last of their heroes and crush the last of their hope. It backfires when he finds himself on the losing side.
- Effective Knockoff: Azmuth comments on the Ultimatrix having "pathetic workmanship", but he deems it worthy enough for Flash to use it at least until he gets his new Omnitrix core working in a few years. It certainly helps that it is built upon the existing Omnitrix structure instead of being built from scratch.
- Empathic Environment: At the start of the chapter, Canterlot is hit with a massive rain storm, reflecting the mood everyone feels after the Negative Ten defeated Flash and his friends and took over the Plumber Base. Flash sits in the middle of it getting soaked during his Heroic BSoD.
- "Eureka!" Moment: During his Heroic BSoD, Flash thinks back to his battle with Shadow and how he was completely out-classed, saying if Shadow hadn't turned back to human form he'd have killed him. But then he stops and realizes Shadow could have killed him, so asks why did he turn back at all, realizing the weakness of the Ultimatrix and how he can beat Shadow.
- Evil Is Petty:
- After Shadow has already been defeated by the heroes, he runs away back into the Plumber Base and overloads the power core so it will destroy everything in a hundred mile radius, declaring he's going to make sure Flash loses by taking away everyone he loves. He doesn't care how many other innocent people will die as a result, or even his own teammates, just as long as he survives in the end.
- Even after Flash stops the power core from destroying the city, the remaining members of the Negative Ten decide to continue fighting the heroes, even when Trixie points out their boss just tried to blow them all up. They just want to take their revenge on the ones that keep getting in their way, as well as make Flash suffer by destroying his loved ones.
- Flaw Exploitation: Flash and his friends use this to defeat Shadow, taking advantage of his pride and need to prove himself Flash's better. When they show up and challenge him to face them alone without help from the rest of his team, they mock him for relying on others when he initially refuses. Unable to stand this blow to his ego, despite the rest of his team warning him it's a trap, he declares he'll handle them all himself and orders them not to interfere no matter what.
- Gray Rain of Depression: The chapter begins with Canterlot getting hit by a rain storm, and Flash, in the middle of his Heroic BSoD, sits outside during it letting himself get soaked.
- Heroic BSoD: Flash goes through one in the beginning. Coming off his defeat against Shadow and the Negative Ten, Flash's will starts to crack from the constant pressure he has faced from being a hero, having to always be the one to deal with threats like Vilgax, Tirek, and Zs'Skayr, only to now face a foe he seemingly can't beat. After a pep talk from Shining Armor though, and thinking back to his last fight with Shadow, Flash figures out how to beat Shadow and his will is renewed.
- Heroic Rematch: After Flash and his friends lost their previous fight against Shadow and the Negative Ten, this time they fight Shadow knowing his weakness and are able to beat him by running out the power on his Ultimate transformation. Then, once Flash has the Ultimatrix himself, he uses Ultimate Volt-Edge to curb-stomp the remaining members.
- Heroic Sacrifice: A non-fatal version happens when Flash sacrifices the Omnitrix's core to stop the base's generator from overloading, essentially sacrificing his powers to save the city. Though it is rendered moot shortly afterwards when he replaces it with the Ultimatrix's core instead.
- Hoist by His Own Petard: Shadow overloads the Plumber Base's power core, making it so that it will explode and take out the entire city with it, intending to survive the explosion using The Worst. But before he can transform, he is struck by a stray bolt of energy and knocked out. Before he regains consciousness, Flash steals the Ultimatrix's core from him, rendering him powerless.
- It Won't Turn Off: After Shadow overloads the base's reactor, he smashes the controls so Flash and Azmuth can't shut it off manually. The only way to stop it is by Flash sacrificing the Omnitrix's core to cancel out the reactor's.
- Living Battery: In addition to being prisoners, Doddery's reason for holding the Rainbooms captive was to regularly drain their energy to maintain her youth.
- Negate Your Own Sacrifice: Flash sacrifices the Omnitrix's core to save the city from the Plumber Base's overloading power core after Shadow sabotaged it. But he almost immediately replaces it with Shadow's own core from the Ultimatrix.
- Phlebotinum Overload: Ultimate Volt-Edge easily overloads Viral when she tries to absorb his energy.
- Rapid-Fire "No!": Shadow lets out several rapid "No!"s when his Ultimatrix runs out of power and he reverts to normal in the middle of the battle.
- Screw This, I'm Outta Here: Devious and Chrysalis decide to cut and run when they hear how Shadow has sabotaged the Plumber Base's power core and intends to blow up the city, effectively ending their alliance with him and the rest of the Negative Ten. This also means that they are the only villains to escape capture.
- Season Finale: This is the fourth and finale one for The Omnitrix Hero. But it is confirmed the series will continue with more stories.
- Sequel Hook: The chapter ends with the Negative Ten defeated, barring Devious and Chrysalis who escaped, and Flash now with the Ultimatrix after sacrificing the Omnitrix's core. This sets up for future stories in the series with Flash now having the Ultimatrix, now as The Ultimatrix Hero instead of The Omnitrix Hero.
- Skyward Scream: After Flash realizes the weakness the Ultimatrix has and how he can beat Shadow, he happily yells up at the rainy night sky "I KNOW HOW TO BEAT HIM!" before running back inside and telling everyone.
- Victor Gains Loser's Powers: Flash steals the core from the Ultimatrix while Shadow is unconscious, effectively turning his own Omnitrix into the Ultimatrix and giving him access to Ultimate forms.
- Victory by Endurance: Flash realizes that Shadow's Ultimatrix has the same power source as his Omnitrix, meaning that his Ultimate Alien forms use up his power faster. He and his friends might not be able to beat an Ultimate Alien in a straight fight, but all they had to do was wait out the transformation. To do that, Flash made sure to use XLR8, his fastest alien, and avoided changing aliens at all to conserve his own power, until Shadow reverted back to normal and was left helpless.
- We Need a Distraction: While Flash, Trixie, and Shining draw the Negative Ten's attention outside and keep everyone distracted by fighting Shadow, Azmuth is able to sneak into the base, free the Rainbooms, and they all sabotage the EMP generator the Negative Ten had prepared.
