The title of the Number One Hero in My Hero Academia was held by All Might for years until the Kamino Incident finally put an end to his time as a Hero. Following him, his rival, Endeavor, took the spot as the Number One Hero and underwent a great change, finally understanding what being a true Hero was all about.
Endeavor, while strong, won't be the Number One forever, and eventually, there are those who will step up to take his place. With countless skilled characters in My Hero Academia, only a few have what it takes to bear the weight and the responsibility of being the Number One Hero.
7 Best Jeanist
The current Number Three Hero, Best Jeanist is an incredibly skilled Pro Hero who has the power of the Fiber Master Quirk. Using his powers, Jeanist can manipulate any fiber that is close to him telekinetically and restrain all his targets with ease.
Although clearly not as strong as the likes of Endeavor, Best Jeanist is quite skilled, as seen when he faced off against All For One and earned his praise. If he manages to improve by training, Best Jeanist could definitely be up for the spot.
6 Hawks
The likeliest person to become the Number One Hero after Endeavor would certainly be the man who holds the spot of the Number Two Hero right now, Hawks. Hawks is one of the youngest Pro Heroes in My Hero Academia, meaning he still has a lot of room to grow stronger. He is a user of the Fierce Wings Quirk which gives him two massive wings and the ability to manipulate all his feathers individually.
Hawks only intends to support the Number One Hero, if the need arises, he wouldn't shy away from the challenge at all. Being a responsible Pro Hero, Hawks would certainly step up and live up to the expectations.
5 Fumikage Tokoyami
Fumikage Tokoyami is certainly one of the most talented students in U.A, which is why Hawks took him under his wing. Tokoyami possesses great potential and he has it in him to surpass even Hawks. With his Quirk, known as Dark Shadow, Tokoyami has a beastly entity living within himself that can bring out terrific power in the dark.
In the Liberation Front War arc, Tokoyami even managed to overwhelm Re-Destro, which is quite a feat in itself. Once he realizes his full potential after becoming a Pro Hero, he could certainly be up for the position of the Number One Hero.
4 Mirio Togata
Mirio Togata is the strongest student in U.A, known to be the man closest to All Might even among the Pro Heroes. It goes without saying that Mirio is going to be up there challenging for the position of the Number One Hero as is expected of someone with his level of strength.
With his Permeation Quirk, Mirio can phase through anything and he's mastered this power to a level where he's almost invincible. He could easily overwhelm Overhaul in combat and during the Liberation War arc, he even defeated several Nomus with rather ease.
3 Shoto Todoroki
Shoto Todoroki is one of the brightest students in U.A and certainly one of the candidates for becoming the Number One Hero in the future. According to Endeavor, Shoto possesses the skill to surpass even All Might as a Hero due to his Half-Cold Half-Hot Quirk.
This power allows him to produce high-temperature flames from his left side and ice from the other. Thanks to the ice side in his body, he can easily regulate the temperature of his body and prevent it from overheating, unlike Endeavor. In the future, Shoto will certainly be up for the position of the Number One Hero.
2 Katsuki Bakugo
Another student with terrific potential, Katsuki Bakugo is quite a powerful aspiring Hero who has sworn to surpass even All Might one day. It goes without saying that Bakugo is one of the strongest of his generation, thanks to the incredible Quirk that he was blessed with, known as Explosion.
Using its powers, Bakugo can produce nitroglycerin from the palms of his hands and then ignite it to create massive explosions. Bakugo tries to keep up with a Deku consistently and for the most part, manages to do so. With time, he's only going to get even better.
1 Izuku Midoriya
The protagonist of the story, Izuku Midoriya is one of the strongest characters in the entirety of My Hero Academia even though he was born Quirkless. Thanks to All Might, however, he received the One For All Quirk the true powers of which could only be channeled through him. Using this Quirk, Izuku can stockpile large amounts of strength and unleash it on his opponents. When used at the maximum power, Izuku could even hurt Shigaraki Tomura.
He also has access to several other Quirks that have been stored inside the One For All Quirk over the years. Out of a possible 7 other Quirks, Izuku had already awakened 4. With their power, he has proven himself to be strong enough to defeat the likes of Overhaul in battle and with time, he'll only get better.