One thing that sets My Hero Academia apart from DC Comics or Marvel is that everyone in their world has quirks. Superpowers don't just go to specific people, but instead are in the hands of everyone. This makes the choice of being a superhero up to the person because everyone has powers so there's no burden of having a great responsibility when everyone else has the same responsibility.
But what sets My Hero's superheroes aside from other superheroes is that their quirks all have limits. Even the most practiced superhero has a limit to their power, and surpassing that limit comes with specific problems. For some heroes, that problem can be dangerous.
10 Half-Cold Half-Hot: When Shoto Doesn't Balance His Quirk, His Flame And Ice Can Cause Him Major Damage
Shoto’s quirk has two drawbacks. If he overuses ice, it will cause his body to experience frostbite. If he overuses heat, his body will start to feel a heat stroke. If he has to use one or the other more it can be a problem, because neither of these drawbacks is going to make him able to fight very well.
However, his drawback is easiest to deal with because the use of one power can cancel out the other.
9 Acid: Mina Ashido's Immunity Can Fade When Her Quirk Is Overused
Mina Ashido can create acid from parts of her body. She can make it more or less dangerous as needed and can use it both to defend and against other people as well. There’s just one problem with her acid: the more she uses it, the less she can defend against it.
Eventually, it damages her own skin as well. However, to continue leveling up as a hero she’s done training to try and negate this drawback, making her acid more dangerous and her body more resistant.
8 Cremation: Dabi Can Withstand His Own Body's Flames
Dabi has the unique quirk of creating incredibly powerful, heated blue flames. He can control his flames better than he should, but unfortunately for him, his body can’t actually resist the heat of the flames he creates.
Though his powers are actually more powerful than his dad, he doesn’t have his dad’s high tolerance for heat. Instead, he has his mom’s high tolerance for cold and actually burns rather easily.
7 Navel Laser: Yuga Gets Sick If He Uses His Power For Too Long
Yuga Aoyama has a quirk that lets him shoot a giant laser from his stomach. That laser’s not a joke either—it can obliterate machines and punch through concrete. But when he was first introduced, using it for more than a single second at a time made him extremely sick.
His costume has helped him learn to control that ability, but he’s also started to build up a tolerance to pain. Making his laser stronger and him able to use the ability for more than just one second at a time.
6 Fierce Wings: Hawks Wings Will Stop Working If He Uses Too Many Feathers
Hawks is able to fly above everyone else, and when he only uses that part of his quirk it’s pretty sweet- but limited offensively. But the character is a lot like Archangel from X-Men in that he can send his feathers out as weapons to attack people.
He can direct how he wants these feathers to be used, inflicting massive damage to whoever hits him. However, Hawks has a very noticeable weakness to fire and the fewer feathers he has the less power he has. Once all his feathers are gone, it can take two days for them to grow back, and he’s helpless until then.
5 Hellfire: Endeavor Can Only Use His Power For So Long Before His Body's Endurance Fails
One of the most powerful heroes, Endeavor is literally covered in flame most of the time. It’s flame that he can generate and control however he wants, and largely flame doesn’t seem to bother him.
However, everyone has a limit and Endeavor isn’t any different. When he overuses this ability, he overheats, making him unable to move as quickly and unable to fight for as long.
4 Erasure: Aizawa's Power Only Works While His Eyes Are Open
Aizawa has the best quirk of anyone else in the series. He can straight up cut off someone’s quirk by looking at them, making them completely helpless. The only problem with this quirk is that it doesn’t have an actual attack mode.
It also doesn’t work if he closes his eyes—he has to keep them open as long as possible. That puts an absolute limit on how long the attack can be used, and no amount of training can surpass that.
3 Electrification: Overusing His Powers Makes Him Unable To Fight
Denki’s special ability is creating electricity and using it to attack opponents with it. He can’t control its direction early on, but that’s not a problem. The problem is that if he goes over a certain wattage limit he becomes basically useless.
His brain shuts down and he’s vulnerable for an entire hour. This means his special move has a one-time usage, which means he has to win when he uses it or he has to have someone pull him out of battle immediately afterward.
2 Dark Shadow: Fumikage Can't Control His Quirk As It Gets Stronger In The Dark
Fumikage has a pretty awesome quirk in Dark Shadow, making him one of the most powerful members of class 1-A. The only problem is, Dark Shadow has to balance between how much power it has versus how much control Fumikage has over it.
In the light or in large amounts of light, Dark Shadow loses much of its power. However, in the dark Dark Shadow becomes far more powerful but Fumikage is much less able to control its ability. Even losing control of his temper makes Dark Shadow difficult for Fumikage to maintain control over.
1 One For All: Deku's Power Is So Great It Can Destroy His Body When He Doesn't Control It
Despite his incredible training his body still can’t withstand his quirk. When he first used it, it literally wrecked him, and he had to learn how to use fine control.
Even now, he can only use it at low percentages. Currently pushing past fifty percent is dangerous. Eventually, he’ll conquer this limitation, but currently One For All is a risky move.