After the complete fall down of the Pro Hero after the war with Shigarki and All For One. Fans are excited to know what brings next to the story of My Hero Academia and especially for the severely injured Deku A.K.A Izuku Midoriya. The next chapter of Deku gonna be Vigilante Deku but it gonna take some time for Vigilante Deku to enter into Anime of My Hero Academia.
So let us break the silence before and know about the Vigilante Deku and also why, when, and how powerful Vigilante Deku is going to be and for a very short summation of the Vigilante Deku is that Deku is going to be the strongest and Darkest Deku we have ever seen in the My Hero Academia. Deku going to be very Dark and choose different paths and can even hurt his friends. So without any delay let us Deep Dive into the full story of Vigilante Deku.
Does Deku become a Vigilante?

Yeah, Deku becomes Vigilante after the War Arc in the My Hero Academia. He becomes Vigilante because, after the severe destruction, injuries, and death of Pro Heroes happened in the Shigarki Vs Deku fight. Deku considers the destruction all happened because of him and it is all his mistake that he failed to stop All For One.
And he shouldn’t have received One For All Quirk and goes on to an Alone mode. Deku decides to stop Shiagrki and All for One by becoming Vigilante Deku. It means that Deku undertakes law enforcement in the city without any Pro Hero Permission or support because after the death of the head of the Pro Hero Government. There is no one and no system for controlling Pro Heroes. So Deku becomes Vigilante to stop the chaos in the city.
How Does Deku become Vigilante?

Let’s get a little further into the full story of Deku turning into a Vigilante. After the Fight with Shigaraki and All For One, Deku is severely injured and spends a lot of time in the hospital. While recovering from the injuries Deku talks with other users of One For All in his subconscious mind and gets to know more about the origin of All For One and One For All from the Past users. Deku also learns how to use the Quikrs of 2,3 and 4 One For All users.
After recovering from his injuries. Deku learns the current situation of the city that the prisoners escaping from Jail, People losing faith in Heroes, and also how the pro heroes are falling apart all about it and he blames himself for all the things that happened in the War and regrets for not being able to stop Shigarki even having One For All Quirk.
Deku Secret Reveal:-
Deku considers he will be a threat to his friends because he is the main target of All For One and he doesn’t want to make his friends hurt. So he decides to not bother his friends or be around them for their safety and decides to defeat All For One alone and leaves the hospital without notifying anyone.

But before leaving Deku reveals the secret of One For All to everyone that he received the Quirk from Almight and he is Quirkless and thanks his friends for being his side. By leaving a specific letter to all of his friends, then on Deku keeps on patrolling the city without getting noticed by any pro hero using the 4th One For All user Quirk Danger Sense and saves anyone who is in Danger. Thus Deku A.K.A Izuku Midoriya turns into the Vigilante Deku.
Vigilante Deku New Ability:–
Vigilante Deku became the strongest Character in the My Hero Academia after the fight with Shigaraki because as we mentioned before that Deku had a meeting with all the previous users when he is in the hospital and Deku get to know how to use all the Quirks of One For All without getting injured.

Also, a new ability is awakened by Deku after the 2 Quirks ( One For All and All For One ) clash in the fight between Deku and Shigaraki. Now All the previous user’s consciousness stored in the One for all quirk is materialized, which means now the past users of One For All can communicate with Deku whenever they want and have a face-to-face talk with Deku in the real world too. This makes Vigilante Deku invincible because now Deku can get guidance from past users and use the One For All Quirks more efficiently.
Will Vigilante Deku be in Season 6?

Vigilante Deku arrives to the Anime version in Season 6 Part 2 of My Hero Academia Anime. Fans are very eagerly waiting for the strongest Deku to enter the Anime. And the writer of My Hero Academia Kohei Horikoshi gave the name for Vigilante Deku as Dark Deku.
Kohei Horikoshi Name for Vigilante Deku:-
In Kohei Horikoshi’s notes of the My Hero Academia, he describes that Deku’s Physical and mental state is very bad, and also Deku is stuck in a Dark Phase in his life and because of it, he gave Vigilante Deku the name Dark Deku. And he also mentioned in the notes that the Dark Deku is going to take a different path than Hero Path and also that he may stay for a while as Dark Deku who can even hurt his friends if necessary.
In What Chapter does Deku become a Vigilante?

In My Hero Academia Manga already most of the Deku story is completed and if you want to read Manga the Vigilante Deku or Dark Deku Arc starts from Chapter 306 Titled ” The Begining of the End ” and the Anime watchers should wait for some time for the Dark Deku arrival. The Dark Deku Arc starts in Season 6 Part 2 of My Hero Academia Anime. Comment down below who is waiting for the Animation version of the Dark Deku Arc.
How Powerful is Vigilante Deku?

Dark Deku has now become the strongest character in My Hero Academia and he is so strong than ever before. Now he can use all Quirks of One For All without even getting injured. Also, after the Fight with All For One, a new ability is unlocked for Vigilante Deku due to the fight between One For All and All For One Quirk. Now all the past One For All user Quirks have become materialized and Deku can talk to the Past users whenever he wants.
Now Deku can get to know all the other One For All Quirks much better and train directly from the past users. This new ability of Deku to see the past users is gonna become a major advantage for Deku and put him on a whole new level of power because now Deku can seamlessly switch from the 7 Quirk of One For All and also additional support is given by the past users to Deku by guiding him in fights through the consciousness stored in One for All Quirk.
This new ability of Dark Deku actually works like when Deku or a Past user of One For All wants to talk with one another. Then Smoke is formed around Deku and the user comes out from Deku through smoke and the past user can talk with Deku face to face. The interesting thing about this ability is that only Deku can see them, the smoke, and face of the user only can be seen by Deku.
This makes it perfect for Deku in fights because now even in the fights Deku can communicate with Past users and get guided by them on how to use their Quriks in certain situations and what are their Quirk drawbacks and everything. More likely, all the Past users can do how Yoichi Shigaraki ( creator of One For All ) stopped his brother from absorbing One For All Quirk from Deku in the fight between Deku and All For One.