It is no secret that My Hero Academia gathers a lot of its inspiration from several different sources. Everything from American comics, classic superheroes, and other anime are all fair game for this bonafide anime hit. But there is one classic shonen anime series that shares themes with arguably the most crucial event in My Hero Academia's storyline--Izuku obtaining One For All. An event with substantial similarity to YuYu Hakusho, where the main lead receives the Spirit Wave Orb.
At first glance, YuYu Hakusho and My Hero Academia could not be further apart in commonality. The main protagonist of YuYu Hakusho is Yusuke Urameshi, a teenage delinquent who wants not to be a hero but is forced into the role. Whereas Izuku Midoriya, the main lead of My Hero Academia, dreams of nothing more than becoming a superhero but does not have powers. Both Yusuke and Izuku are underdogs because they lack abilities but are given powers when duty calls, especially when it comes to an essential aspect of becoming a hero--the training.
Both heroes are put through excruciating training by their mentors. Much like Yusuke and Izuku, who are opposites of each other, their respective trainers, All Might and Genkai are two different sides of the same coin. All Might chose Izuku because beneath his shy demeanor and lack of natural-born powers, he saw courage and the willingness to use that courage for good. On the other hand, Genkai does not care if someone is "good" or "evil" because when she sees potential, she nurtures it, no matter who carries it. This was the point of her tournament arc in Yu Yu Hakusho, finding her successor and passing on her spiritual power and knowledge. Purely meritocratic in her approach, unlike All Might, whose main reason is based around heroic ideals.
Even though their reasons for choosing a successor are different, All Might and Genkai's methods are equally grueling. Both Izuku and Yusuke trained and pushed beyond their limits, feeling like they were about to collapse at points in their training. All Might is more encouraging in his approach to moving Izuku along, providing inspiration and determination, whereas Genkai needed a more harsh system. Genkai would berate, bully and even beat Yusuke within an inch of his life to bring out the full potential of his spirit energy. This makes sense as unlike Izuku, Yusuke is much more of a hard-headed kid, and Genkai would not put up with any of his nonsense. In Genkai's mind, if Yusuke died from her training, his death meant he was not strong enough--a Darwinist approach to building her pupil up. Yusuke and Izuku were not necessarily prepared for such activity, but it was do-or-die to gain their respective powers.
Do-or-die is not a metaphor in these situations as gaining either One for All or the Spirit Wave Orb can kill the user if they're not ready. In Izuku's case, if he did not go through intense physical training, the power of One for All would, quite literally, blow his body apart. As for Yusuke, Genkai infusing the Spirit Wave Orb is just as dangerous and extremely painful since such a sudden transfer of power is a lot for the body to take. Like the Spirit Wave Orb, One for All is a culmination of the knowledge and abilities from within the master to be passed on to the pupil and requires an indomitable will and great physical fortitude. Still, in typical shonen hero fashion, Izuku and Yusuke proved more than worthy of surviving a transfer of such power in a short time.
Both Yusuke and Izuku, although having different mentors with polar opposite motives, faced the same painful training but came out with powers that were manyfold their previous abilities. Both also grew in mental fortitude and were more resolved in their goals. Pain is a great teacher, and the moral of the story is that even when times are tough, pushing through can make a hero out of anyone.
