One For All is arguably the strongest Quirk in My Hero Academia, and Izuku Midoriya is its current user. Izuku is a selfless aspiring Pro Hero, but Deku became a vigilante because he did not want to put his classmates and friends in more danger. This version of Izuku is known as Dark Deku, and he was able to beat multiple Villains in this state. With the amount of power Dark Deku had, he could have easily defeated several Pro Heroes as well.
Source：https://www.cbr.com/pro-heroes-vs-dark-deku/
