Warning: contains spoilers for Undead Unlock chapter 77!
Part of My Hero Academia's immense popularity is how each villain's heart-wrenching backstory both humanizes them and presents the possibility that they might not be wholly evil, but that pattern is flipped in Undead Unlock. That underrated manga features a cast of heroes who share pasts that are even more tragic, to the point where fans wonder how they didn't become villains.
Undoubtedly the most notorious of My Hero Academia's villain origin stories belongs to Tomura Shigaraki, who was mentally and physically abused by his father whenever he showed any inclination that he may be interested in heroes. His trauma was so extreme that when the awakening of his Decay quirk accidentally killed his family, what started out as fear and horror soon evolved into a state of almost contentment in Shigaraki's tormented mind. However, he ultimately blocked the traumatizing experience from his memory, causing him to become violently ill when he later remembered what happened. Shigaraki's dark past has made him a subject of sympathy among fans, and yet Undead Unlock's heroes have it even worse.
So far, the origin story of every Undead Unlock hero with powers - called Negators - has been utterly tragic, many of them sharing the unsettling characteristics from Shigaraki's own disturbing experiences. In chapter 30, Chikara Shigeno recounts the day he crossed a busy street ahead of his parents. When he turns around to look at them, his Unmove ability (which causes anything that's in his line of vision to freeze) awakens right as his parents begin crossing the street. Of course, a truck just so happens to come barreling down the road at that very moment.
In chapter 77, readers learn that Top Bull Sparx grew up poor in a neighborhood where winning a sports scholarships was his and his friends' only hope of escaping. On the night before a race that will be either Top's or one of his friends' ticket out, Top decides he'll voluntarily lose, because he doesn't want to win at the expense of his friends' happiness. Sadly, when he starts to slow down in the middle of the anticipated race, his Unstoppable ability kicks in, causing him to run at insane speeds, maiming one of his friends and killing the other two. In addition to Shen, whose ability both caused his sister to fall off a cliff and compelled his master to orchestrate the accident, there's Undead Unluck's Undead Andy and Fuuko Izumo, whose origins are even darker.
In My Hero Academia, Shigaraki's comrades each possess a tragic story, but come nowhere close to his own, while in Undead Unluck, the devastating past of every hero essentially matches or exceeds Shigaraki's history in grim tragedy. While heartbreaking, it's understandable why Shigaraki and his associates became villains, leaving open the question of whether they can be saved. In contrast, Undead Unluck asks how its heroes managed to avoid submitting to the darkness that has been thrust upon them.
Their suffering comes as a result of Undead Unluck's god, a sick sadist who finds enjoyment in tormenting its creations, choosing to awaken their powers at times that will cause them the most pain. This accomplishes more than just adding a deterministic factor to their plight - in fact, most of them joined the Negator organization known as Union because it endeavors to kill this god. Although portrayed as the good guys, the Union is made to look more heroic by comparison, as the only other group of Negators is Under, made up of members who simply want to abuse their powers to accomplish their own goals. Undead Unlock asks dark questions about personal morality, offering readers a very different experience to My Hero Academia, though both series accomplish depth by examining the intersection of utter tragedy and unexpected power.