While many anime center on a "chosen one," the idea of the anti-chosen one somehow appeals just as much, if not more, to viewers. There's been a recent upswing in shonen heroes who are the runts of the litter or lack some key element that everyone else in the universe has.
This trend actually dates back to anime's origins. For every new shonen hero like Deku from My Hero Academia, who was born Quirkless, there's a classic hero in a similar situation. After all, Goku from Dragon Ball is supposed to be weak among the Saiyans and starts Dragon Ball Z weaker than even Raditz.
Over time, the anti-chosen one trope has only gotten more extreme. Take Mashle: Magic and Muscle's protagonist Mash. He's one of the few people who cannot use magic but displays other skills through hard work. Ultimately, characters like Mash show why the anti-chosen one is such a popular trope: it creates an identifiable protagonist who is at an inherent disadvantage but still rises above with sheer willpower.
What Is An Anti-Chosen One?
The concept of the anti-chosen one is not necessarily anyone who isn't the chosen one, nor is it an anti-Christ figure destined to bring ruin rather than joy. Rather, it's a character who's born with certain limitations that set them apart from everyone else -- yet they become great regardless. In a world where everyone has magic, this character does not.
This is not the same as, say, a character who's out of their element but learns how to harness their power, nor is it one with immense power that's sealed away. Neither Naruto nor Bleach's Ichigo are anti-chosen ones. Nor is it a character who looks unassuming at the start but actually has incredible abilities.
The character's disadvantage has to remain throughout the narrative and/or inform any of their life experiences. While Deku does gain One For All despite being born Quirkless, his inexperience with Quirks is a consistent challenge he needs to overcome. On the other hand, a character like Mash has no magic throughout Mashle but his physical strength compensates entirely for that.
In essence, the anti-chosen one is special in that they are weaker than those around them. However, this disadvantage forces them to use their limited skill-set to become just as good as everyone else -- and eventually surpass them.
Why Do People Like Anti-Chosen Ones?
Fans love anti-chosen ones because they are easily relatable. The average person isn't born special or gifted with incredible power. We all feel outmatched by those around us at times, making it easier to identify with an anime protagonist in a similar mindset. In turn, when that character then turns out to be incredible because of or despite their weaknesses, viewers can live vicariously through them.
Asta in Black Clover is born as a failure. He cannot manifest magic despite living in a world where it's prevalent. We empathize with him as a result of this vulnerability. Like many people, Asta has massive dreams and ambitions but lacks the means to achieve them without a little help.
In this sense, kids who might feel vulnerable or disadvantaged in life may find themselves empathizing more with a character like Deku than Ichigo. Most shonen series revolve around strong people becoming stronger. Goku is an odd inversion in this sense since he begins Dragon Ball as strong by Earth's standards but then learns he's a low-class member of his species, the Saiyans. Through intense training, he becomes the hero. That makes Goku more relatable to audiences than just being a wild child who grew up in the woods and never met a girl.
The Comedic Potential of the Anti-Chosen One
There's also a lot of comedy in the anti-chosen one setup. The isekai anime Konosuba centers around a protagonist who is reborn into another world with a Goddess. Every member of his core crew is an Anti-Chosen One of sorts. Aqua is a pathetically weak Goddess who, despite having great power, is inept in all regards. Megumin is an all-powerful sorcerer with one spell that totally exhausts her after a single-use. Darkness is a physical tank who enjoys taking damage. The main character, Kazuma, is just a generic guy -- which puts him at a huge disadvantage in a fantasy world, as he needs a massive training montage to even begin going on adventures. All four of them are ill-equipped to deal with their world. They are all anti-chosen ones.
The reason for this, however, is not to tell a complex, serious story, but to make the audience laugh at the characters' expense. They are a punchline, designed to deconstruct and parody the power fantasies inherent in the isekai genre. Shows like That Time I Got Reincarnated as a Slime or Sword Art Online feature a protagonist who is utterly indestructible, capable for any and all situations. Konosuba turns that on its head by presenting characters who are unusually unprepared.
The same is true for Mashle. In theory, it has the same setup as My Hero Academia: in a world where magic is the norm, a person without magical ability rises above due to sheer physical effort. However, while My Hero Academia plays this up for dramatic and action-packed effects, Mashle plays it up for comedy. The absurdity of Mash's strength is a joke meant to make audiences laugh, especially due to how ill-fitted he is to his world.
The anti-chosen one breaks the logic of their world on their path to success. In these cases, we're not laughing at the protagonist or cast, but rather the world they deconstruct.