My Hero Academia has some incredible characters with some powerful Quirks, like Katsuki Bakugo and Tomura Shigaraki. These characters either use their Quirks to protect mankind or to gain power and control over the masses. But what would happen if our pro-heroes stopped being heroes and our villains decided to turn away from a life of crime?
In everyday life, powerful Quirks perfectly suited to hero work could quickly turn useless. Although the majority of Quirks are helpful in some way, a flashy and powerful Quirk wouldn't necessarily benefit you when it comes to daily chores and normal careers -- just imagine Bakugo as an accountant, for example. And so, here’s a look at some of the most “powerful but useless" Quirks when it comes to everyday living.
"Dark Shadow" - Fumikage Tokoyami
Fumikage Tokoyami’s quirk is "Dark Shadow." He’s able to manifest a shadow monster that somewhat resembles him to attack his enemies. Dark Shadow grows more powerful when it is surrounded by darkness, but becomes more difficult to control. Meanwhile, in the light it is much weaker and smaller, but easier to use.
Although it may be cool to have a Pokemon-like pet as a Quirk, Dark Shadow would be rough to use in everyday tasks. The main issue is that the Quirk is negatively impacted by any sort of light, which means you couldn't use it for many daytime tasks or a practical 9-5 job that involves being in the sun. The idea of having a helper that's stronger than you to help with physical tasks is a nice idea, but only if they're actually stronger than you, which might not be the case with Dark Shadow in the daylight.
"Navel Laser" - Yuga Aoyama
Yuga Aoyama has one of the flashiest Quirks: "Navel Laser," which lets him fire a sparkling laser from his navel for a brief period. The laser is powerful enough that it can blast through concrete, but, if Aoyama overuses it, he will suffer from stomach pains. Powerful and flashy, Aoyama’s navel laser could come in handy when you need a light show at a club but, other than that, there isn’t much practical use for a laser that comes out of your belly button, especially if it gives you stomach aches. Ironically, Aoyama's joke Quirk is much more useful in battle than it would be in literally any other scenario.
"Bloodcurdle" - Chizome Akaguro
Stain’s Quirk, “Bloodcurdle,” lets him paralyze his enemy for a significant amount of time once he consumes their blood. The lasting effects of the paralysis are dependent on the person’s blood type. Much like Himiko Toga, another character with a blood-dependent Quirk, if Stain decided to turn away from the world of crime, there isn’t much he could do to make his Quirk worthwhile. Stain could use his Quirk for anesthesia purposes, but he can only paralyze a person, not prevent the actual feeling of pain. Beyond that, consuming someone's blood seems like a lot of trouble to go to for anything besides a fight.
"Transform" - Himiko Toga
Himiko Toga’s Quirk is "Transform." She’s a shapeshifter who can physically transform into anybody by consuming their blood. She can hold her shapeshifted form depending on how much blood she ingests from the person she's impersonating. Later on in the series, she eventually learns how to mimic a person's Quirk abilities. Yet, this aspect is a power boost to her actual Quirk.
Toga’s Quirk is perfect for her current criminal lifestyle. But if she chose a more average life for herself, she'd quickly find herself in a bind. The issue with this Quirk is transforming in the first place. Transform requires blood to work, which isn't exactly easy to get ahold of (safely, casually or legitimately), especially if Toga were wanting to shift into a specific person. At best, she'd be able to turn into randos from the blood bank, at worst, she'd never get to use her Quirk at all -- even if an ordinary occasion called for her to become someone else.
"Gigantification" - Yu Takeyama
Mt. Lady’s Quirk, “Gigantification,” allows her to go from her normal height, 5’4” (162 cm), to a towering 62’8” (2062 cm). Mt. Lady’s gigantification gives her proportional strength and abilities but, even as a pro-hero, her Quirk isn't always helpful (as seen in the anime's very first episode). Unfortunately, there's no spectrum between Mt. Lady's base height and giant height: she’s either her normal human height or a gigantic version of herself.
From one point of view, gigantification seems like a useful Quirk because you can quickly sprint to a location, and you have giant-sized strength. However, Gigantification is only really useful when you can roam freely like a Titan in the open field. Yet, if Mt. Lady lived in the city, her Gigantification would be more of a nuisance to others because she would destroy private property and may run over civilians. In other words, she wouldn't be able to control her strength. She would also need specialized everyday clothing that is stretchy enough for her to transform between heights. It is also unlikely that support companies would provide costumes or any everyday wardrobe for non-heroes.