One theory suggests that Yajirobe could have become the strongest human in the Dragon Ball universe. In the history of the anime, the katana-wielding warrior has a reputation as one of the weakest - as well as one of the laziest - heroes in the franchise. Introduced in the original Dragon Ball series, Yajirobe is counted as a friend to the main characters, but not someone who actively fights beside them in battle.
Not unlike the situation with most characters in the anime, there was a time when Yajirobe was considered formidable. However, those days have long since passed. In fact, he stepped away from the action even earlier than Chiaotzu. Based on the current power scale in the Dragon Ball franchise, it's safe to say that Yajirobe is well below the level of every Z-Warrior. He's still stronger than most humans (including Videl and Mr. Satan), but is considerably weaker than Master Roshi, Yamcha, Tien, Krillin, and even Chiaotzu. But in spite of how weak he really is in comparison to everyone else, it's been postulated that the samurai could've outclassed all of his fellow Earthlings. Here's what this theory says about the future Yajirobe could have had in the Dragon Ball anime.
Yajirobe Used To Be Dragon Ball's Strongest Earthling
Yajirobe is a long way away from being the strongest human, but there is evidence that proves he was the most powerful member of his race at a certain point. When he fought Goku in his Dragon Ball debut, he and the Saiyan were on par with each other. During the fight, Goku was so surprised by Yajirobe's strength that he claimed to have never met someone as tough as him. In making this comment, Goku was basically saying that Yajirobe was more powerful than Krillin, Tien, Yamcha, and Roshi, all of which being characters the Saiyan was previously acquainted with. And based on what happened in the fight, there's no reason to suspect that Goku was exaggerating. He had already surpassed the aforementioned characters, meaning that none of them would have been as difficult to beat as Yajirobe was.
What Makes Yajirobe's Power Level So Impressive
Most of Yajirobe’s backstory before meeting Goku is unclear, though it is known that he spent a large portion of his life in the woods, fending for himself. His isolated lifestyle in the original Dragon Ball anime has a lot to do with what made his power level seem so impressive at the time. Goku had to go through all sorts of trials and intense training to get where he was in the timeframe of their fight. Yajirobe, on the other hand, achieved a similar degree of power through a much less eventful journey and presumably, significantly less training.
It's important to note that Yajirobe didn’t develop an appreciation for training and exercise after his debut either. But in spite of that, he easily bested Krillin when they sparred in the Saiyan Saga. Based on that win, it stands to reason that he would have beaten Chiaotzu and could have posed a challenge to Yamcha as well. What’s interesting about that is this notion that Yajirobe didn’t need hard work to be a competent fighter.
Yajirobe Could've Kept Up With Dragon Ball's Human Z-Warriors
Of course, Yajirobe’s natural talents could only get him so far. By his own admission, the four Earthlings eclipsed him through the months they spent preparing for the fight with Nappa and Vegeta. The gaps between them only continued to widen as time went on, and it was all due to Yajirobe’s aversion to physical activity. His laziness and overall lack of interest in training kept him from progressing as a fighter. But if he had practiced alongside the others, Yajirobe could still be counted as a Z-Warrior today.
It's been speculated that because Yajirobe was once stronger than the other human Z-Warriors, he could have maintained that advantage if only he had tried. Theoretically, developing a better work ethic and training for the fight with the Saiyans, the battle with the androids, and more could have made him a force to be reckoned with. Given that he is a human, there’s obviously a limit to what he could have accomplished, as he was incapable of keeping up with Goku. But looking at what he could do in the original series, it’s not impossible that he could have stayed on the level of the franchise’s human protagonists. Not only that, but there’s at least a chance that he could have been able to keep any of them (even Tien) from surpassing him.
What If Yajirobe Had Gotten Stronger?
It's worth wondering what would have become of his character had his full potential ever been realized in the anime. If he didn't slack off on his training at Kami's Lookout, he would've been strong enough to join the Z-Warriors against Nappa and Vegeta, as opposed to just watching from a safe distance. But, Yajirobe being slightly stronger than Tien and Yamcha wouldn't have been enough to turn the tide against Nappa, much less Vegeta. In fact, Yajirobe staying out of it until the end actually paid off for them. Had he died earlier, he wouldn't have been around to set up Vegeta's defeat by cutting off his tail and reverting him back to his base form.
A stronger version of Yajirobe would have been in a position to play larger roles in other Dragon Ball Z storylines. For instance, he could've taken part in the search with the androids and the fight with the Cell Juniors. But, it shouldn't be forgotten that the human Z-Warriors weren't powerful enough to make a difference in those fights. So even if he was stronger than them, Yajirobe likely wouldn't have fared much better, but at least could've had a hand in the fighting. And similar to what happened with Tien, Krillin, Yamcha, the character's relevance would have fallen further and further as Goku and Vegeta continued to gain in power. Even the strongest human wouldn't be a match for Majin Buu or any of Dragon Ball Super's villains.
With that being said, Yajirobe might have been a candidate for a spot on Goku's Universe 7 roster for the Tournament of Power. Rightfully, he wasn't on Goku's radar when Dragon Ball's Z-Warriors were putting together their team, but had he trained vigorously instead of succumbing to his laziness all those years ago, Goku could have considered picking him over Tien, Krillin, or Master Roshi. Unfortunately, Yajirobe just didn't have it in him to work that hard.