15 Anime Characters Who Start Off Weak But Totally Power Up

At the beginning of My Hero Academia, Izuku Midoriya has no special abilities to speak of; he's just a regular middle school kid. This is a problem, considering he wants to be a superhero and the vast majority of his classmates have superpowers, which they call quirks. When Izuku does get a quirk of his own, he has to endure a merciless training program and multiple encounters with villains before he's able to harness a fraction of its full potential.

While he still has a long way to go, he makes incredible progress in a short time, and can soon hold his own against villains.

At the start of Tokyo Ghoul, Ken Kaneki is a shy college student who loves literature and lives in denial of his familial issues. When he's attacked by a ravenous ghoul named Rize, the two of them get into an accident that destroys his organs, requiring them to be replaced with ghoul parts.

Suddenly, he craves human flesh, and finds himself embroiled in the underground world of ghouls. At first, he simply wants to ease into his new life with minimal trouble, but after being taken and put through misery, his personality does a complete 180; in light of the incident, he's willing to fight for what he wants.

In Black Clover, Asta lives in a world of magic despite having no magic powers himself. And while everyone around him doubted his abilities, he still made it his goal to become a Magic Emperor and worked hard to become a strong Magic Knight. He found a way to turn his minuses into pluses by wielding Anti Magic. He goes from a weak non-magic user to a 3rd Class Junior Magic Knight who's a part of the elite Royal Knights squad.

After Shinichi Izumi of Parasyte becomes infected with an alien parasite, he's understandably horrified. He has no idea how to handle Migi, who has taken over his right hand, and all he can do is panic.

Eventually, he learns to work with Migi (rather than against him) to achieve his goals of defending humanity and keeping his deformity a secret. By utilizing teamwork, Shinichi is able to protect Earth from a parasitical onslaught, which would have been impossible at the start of the series. 

When Bungo Stray Dogs begins, Atsushi Nakajima is close to dying of starvation after being kicked out of an orphanage. He ends up joining the Armed Detective Agency at the behest of one of its members, Dazai. At first, he has no discernable abilities, and when it becomes clear that he's accidentally transforming into a dangerous tiger, he becomes more of a liability than anything else.

As time passes, however, Atsushi learns to control his transformations. On top of that, his mystery solving prowess increases, and he becomes a crucial voice of reason and morality in the agency.

The primary focus of this great anime is class 3-E, all of whom initially seem weak and unmotivated, but achieve their full potential with the help of their teacher, Koro-sensei. As such, most of the characters experience polar attitude shifts, but the series protagonist Nagisa Shiota's is perhaps the most notable.

Nagisa starts the series off with no real direction. Due to a turbulent home life, he's depressed, and is performing poorly in school. However, when Koro-sensei — a tentacle monster with a smiley face for a head — becomes his middle school teacher, he and his classmates are challenged to eliminate the creature if they want to save the planet. The process of becoming powerful enough to actually eliminate their teacher sharpens him physically and mentally, and also helps him learn to work with others.