Quirks are special abilities that around 80% of the society in the world of My Hero Academia possess. While the usage of Quirks is generally regulated, Heroes and Villains are its most extensive users in the entire series. Almost every Quirk in the series seems to have extraordinary power, but strong as these abilities are, there are some limits to them.
Interestingly enough, there are some Quirks that have broken past these limits and this phenomenon has been described as 'Awakening' in the series. Only a handful of Quirks have shown their Awakening so far. Here are 5 Quirks that have already awakened, and 5 which are very close to awakening.
10 Awakened: One For All
One For All is currently wielded by Izuku Midoriya, who is also its 9th user. Although the Quirk has had 8 users before him, none have displayed the abilities that Izuku has. During the Joint Training arc, Izuku was able to manifest another ability of the One For All Quirk, known as Black Whips.
This ability manifested through a former user of the Quirk. According to the user, the One For All had stored bits of the power of all the previous users, thus giving Midoriya access to 7 more Quirks in the process. One For All's awakening isn't complete yet, but its first step is already underway.
9 Close To Awakening: Half-Cold Half-Hot
Half-Cold Half-Hot is the Quirk of Shoto Todoroki, the son of Endeavor. Since he was a child, Shoto had been training to master the left side of his body. Even then, he hasn't mastered the fire abilities, such as the Flashfire Fist, so far and it'll take him a bit more effort to pull it off.
Shoto's use of the Flashfire Fist, when combined with his right side, could lead to Half-Cold Half-Hot's awakening, and take his abilities to the next level. Thanks to his training under Endeavor, Shoto had a decent chance of awakening his Quirk and since the League of Villains is approaching, now would be the perfect time to go beyond his limits.
8 Awakened: Decay
The Quirk of Shigaraki Tomura, Decay was first awakened when he was a child, and in the event, he massacred his entire family. In his fight against Redestro, Shigaraki managed to awaken his Quirk and push beyond all his limits.
With his newly acquired powers, he can now decay things that he isn't even directly touching, and the speed of his decay has increased significantly as well. He was able to push Redestro to 100% stress level, and still, remain dominant in the fight. Decay's awakening makes it one of the most destructive Quirks in the entire series.
7 Close To Awakening: Explosion
Bakugo Katsuki's Quirk, known as Explosion, lets him produce nitroglycerin from the palms of his hands and ignite it to create huge explosions. Using this frightful ability, Bakugo has become one of the brightest Hero students in U.A, but his Quirk needs to awaken soon.
Midoriya and Bakugo always progress together. Since Midoriya has managed to awaken the One For All to some extent, Bakugo has to step up too. Although his Quirk hasn't awakened yet, it is only a matter of time before it does. Under Endeavor's training, Bakugo is surely going to push beyond his abilities, and prepare as the Villains approach.
6 Awakened: Transform
Himiko Toga's Quirk, called Transform, allows her to take on the appearance of anyone whose blood she ingests. Once the blood is consumed, she can copy a person down to their smallest of nuances. However, how the copy behaves depends completely on how much information Toga has about her victims.
Surprisingly, there is another level to his Quirk which was recently unlocked by Toga during the Meta Liberation Army arc. Once ingested, the blood doesn't just let her copy someone's appearance, but she also gets the ability to use their Quirk, which makes Toga's Transform frightening to use. The extent of her copied Quirk abilities remains largely unknown.
5 Close To Awakening: Hellflame
Hellflame is the Quirk of the current No. 1 Hero, the Flame Hero, Endeavor. With this ability, Endeavor can create and manipulate flames according to his will. Even though the Quirk is extremely powerful, there's a certain limit to its powers. Once Endeavor uses his flames for too long, he cannot see properly and his movements become sluggish.
However, in his fight against the enhanced Nomu, Endeavor was capable of pushing beyond this ability for a while. As evident, this is slightly different from what Shigaraki experienced, but Endeavor could be close to awakening as well, and with the impending threat of the Paranormal Liberation Front, he needs to go Plus Ultra and become the pillar for everyone.
4 Awakened: Ice Manipulation
The unnamed Ice Manipulation Quirk is wielded by Geten, who was formerly a member of the Metal Liberation Army and is now a lieutenant of the Paranormal Liberation Front. Geten's Quirk lets him use the powers of cryokinesis and control ice at his will.
In his fight against Dabi, he gave him a very hard time and managed to hold him to a stalemate, despite the former having a fire Quirk. Just like Shigaraki, Geten's Quirk has also shown signs of evolution. Once evolved, his Quirk lets him control the temperature of Ice at will, making him an even bigger threat than he was prior to gaining access to this power.
3 Close To Awakening: Hardening
One of the students of Class 1-A, Eijiro Kirishima possesses tremendous capabilities and the potential to become an incredible Hero. His Quirk is known as 'Hardening', and it lets him harden any part of his body to a certain extent. Over time, this ability of Kirishima has only been evolving, getting stronger with more training.
In the Shie Hassaikai arc, Kirishima was able to push his Quirk to a new level, which was referred to as 'Unbreakable Mode'. Using its powers, Kirishima became strong enough to match some of the strongest members of the Shie Hassaikai. Although it was never clarified whether this was awakening or not, it is believed that Kirishima's Quirk has more potential to fulfill, and could thus awaken in the future.
2 Awakened: Double
Belonging to the League of Villains' Jin Bubaigawara, also known as Twice, Double is an extremely useful Quirk. It allows Twice to make two copies of himself, both of which are strong, and capable of their own thoughts.
Although this Quirk was limited to multiplying two times until recently, Twice managed to take its powers a step further and now his clones can further clone themselves twice, making this process infinite. According to Giran, Twice's powers have grown to a level where he can take down a country by himself, making him one of the strongest members of the League of Villains and an important asset to the Paranormal Liberation Army.
1 Close To Awakening: Permeation
Mirio Togata is one of the U.A's Big Three, and the man who was once said to be closest to All Might. Although Mirio lost his Permeation Quirk when hit by a bullet during the Shie Hassaikai arc, his Quirk will, more likely than not, return to him at some point.
Once back, Mirio could gain access to a new side of his Quirk that we haven't seen previously. Similar to how Shigaraki re-awakened his Quirk, Mirio can undergo a similar process, and hopefully, get his Quirk back once again.