Introduced about midway through the Majin Buu arc, Fusion impacted Dragon Ball quite a bit at the end of its life. It more or less went on to dominate the rest of the Buu arc, only fizzling out for the final battle against Pure Buu. Fusion’s always been a bit love it or hate it for most fans. It leads to powerful new characters– often entertaining in their own right– but the mere concept of fusion undercuts the tension.
Not just that, it seemingly goes against the series’ core themes of self-betterment for the sake of it. A martial artist isn’t going to show off the fruits of their labor by becoming another being entirely. In general, fusion may not be as poorly defined as time travel was in the Cell arc, but it’s a technique with some glaring holes in its concept.
10 Height Matters, Except When It Doesn’t
Pretty much the first rule that’s established about fusion is the fact that both fusees need to be of a similar height. While Goten and Trunks prove right away that fusion participants can get away with some wiggle room, they’re essentially the exact same height. For all intents and purposes, being the same height is a fusion rule.
Except when Goku and Vegeta fuse, apparently. A considerably shorter man than Goku, the two can fuse comfortably with no issues whatsoever. Fusion Reborn even conveniently ignores Vegeta’s canonical height, giving him a nice growth spurt in between his death and… well, not much else.
9 The Time Limit Has No Narrative Weight
The fusion dance’s time limit is a really good concept. On paper, at least. In execution, this idea is more of a narrative nuisance than anything. It’s never actually utilized well for tension purposes, instead serving as the rug that will inevitably be pulled from under Gotenks’ and now Vegetto’s feet. It’s a miracle Gogeta didn’t defuse in DBS: Broly.
Now, this isn’t to say the sudden unfusings aren’t dramatic– they generally are– but Toriyama uses them as a predictable get out of fight card consistently. Gotenks was never going to defeat Majin Buu in the same way Vegetto was never going to defeat Zamasu. They have to defuse, but they can’t wait for the time limit in place. The solution? Just ignore it completely because “too powerful!”
8 Super Saiyan 3 Gotenks
Speaking of too powerful, Gotenks’ relationship with Super Saiyan 3 is rather… interesting, to say the least. Upon seeing Goku transform as Goten and Trunks, Gotenks is just able to turn Super Saiyan 3. The story even comments on this outright, basically pushing the issue aside as it did with Goten being able to turn Super Saiyan.
To Akira Toriyama’s credit, though, Gotenks having Super Saiyan 3 is handled funny enough and is in-line with the Buu arc trivializing Super Saiyan forms. Even in-universe it makes absolutely no sense why Gotenks can turn Super Saiyan 3, but it’s handled with enough Dragon Ball charm where it’s funny rather than annoying.
7 The Potara Solution
The Buu arc presents the Potara Earrings as the very real and very permanent alternative to the fusion dance. Nothing in the story implies it’s impermanent. Not just that, Toriyama goes out of his way to prove it. Rou Kaioshin has been fused for years, and Kaioshin and Kibito end the series permanently fused.
Of course, Dragon Ball was never going to be able to end without Goku as, well, Goku, so Vegetto had to go. The workaround in the original canon ending up being “mysterious air” inside of Majin Buu. There’s no real attempt at making sense of what happened outside this throwaway line, and it’s never brought up again.
6 The Potara Retcon
As ridiculous as Goku’s reasoning for Vegetto defusing is, it was an absolutely necessary step Dragon Ball needed to take. Goku and Vegeta couldn’t remain Vegetto for the end of the series, but Toriyama couldn’t just bring the potara’s rules either. Mysterious air is a cop-out, but it’s one that exists to avert trivializing Potara Earrings.
Not that it matters because the Goku Black would just go ahead and retcon it anyways. It turns out that there’s no meaningful difference between the fusion dance and potara fusion anymore. There are still some differences, but they’re all surface level. This retcon didn’t even need to happen since Vegetto has no place appearing in Super anyways.
5 Vegetto’s Clothes
In the Buu arc, Vegetto’s clothes make perfect sense and stand as a nice visual contrast to Gotenks. He’s just wearing a blend of what Goku and Vegeta were wearing at the time. It makes perfect sense. In the Goku Black arc in Dragon Ball Super, though? Vegeta’s wearing an entirely different outfit.
His armor’s beaten up a bit, but it’s still rather blatantly his Cell arc armor and not his Buu arc spandex. Realistically, Vegetto probably should have formed with Vegeta’s armor on. That he doesn’t suggests that these will just be Vegetto’s clothes whenever he shows up. Though Dragon Ball Heroes does counter that notion.
4 Vegetto’s Name In English
Whether it be the anime or manga, Vegetto’s name in English has some serious problems. In Japanese, it makes perfect sense. Vegeta and Kakarotto make Vegetto. Vegeta and Kakarot make… Vegito and Vegerot? To Vegito’s credit, it at least sounds like the right name and isn’t a viciously incorrect translation of the name.
Neither is Vegerot, granted, but it just doesn’t sound all that pleasant. In fact, Vegerot sounds downright gross. The manga probably would have been better of just calling him Vegetto and never acknowledging the Kakarot/rotto dilemma, but Vegerot at least keeps the naming scheme consistent. For better or worse.
3 Making Sense Of The Rival Boost
Fusion already greatly amplifies the strengths of its participants– dance or otherwise, it seems– but the Rou Kaioshin makes a very interesting observation after Vegetto is formed. He mentions that Goku and Vegeta’s relationship has amplified Vegetto exponentially. Not just that, this idea is brought back into play with Kale and Caulifla fusing into Kefla during the Tournament of Power.
It’s overkill more than anything, but one does have to wonder why Toriyama even included this detail in the Buu arc. Perhaps it’s just to further assert how dominant Vegetto is, but shining a spotlight specifically on the rivalry between Goku and Vegeta is something Toriyama rarely does outside the context of Vegeta’s own ego.
2 Goku Hid Fusion For Too Long
Despite going on about responsibility and the living needing to take care of themselves, Goku does not set a good example during the first half of the Buu arc. He messes up so badly that the theme of responsibility ends up tying back into him needing to take responsibility. His reasoning for hiding Super Saiyan 3 makes enough sense, but fusion? Goku should’ve mentioned that asap.
The moment Kaioshin mentioned Buu, Goku should have revealed that he knows how to fuse. That he didn’t just mention it casually earlier on is also strange. He’s come back after years of training in the afterlife, but he’s surprisingly quiet about what went down over there. Granted, he only has time to mingle for a few hours.
1 The Characters Who Would Benefit The Most From Fusion Don’t Use It
Goku teaching Goten and Trunks fusion? Perfect sense. They’re a natural pair and are two characters who would make great use out of it! Teaching absolutely no one else fusion? Well, now that’s not quite as helpful. Sure, Krillin isn’t tall enough to fuse with anyone, but Yamcha and Tenshinhan could make good use out of the dance.
It’s also just handy to know. At the moment, Goku, Vegeta, Piccolo, Goten, and Trunks are the only characters who know the dance. Krillin’s done the moves in the past, but it’s unlikely he’d remember them. Not that it matters for him.