The following contains spoilers for My Hero Academia Chapter 355, "Extras" by Horikoshi Kohei, Caleb Cook and John Hunt, available now in English from Viz Media.
My Hero Academia's final arc is tying up several of its characters' stories so subtly that it's easy to ignore that they've occurred at all. After the flashy firefight that was Dabi vs Todoroki Shoto, it would be easy to miss quieter conclusions to previously unresolved narratives such as Tokoyami Fumikage's long-awaited team-up and acknowledgement by his mentor, Hawks. When All For One incapacitated Endeavor, Tokoyami wasted no time in rushing over to assist Hawks with one of the war's most dangerous battles with his classmate, Kyoka Jiro.
When Tokoyami first showed up, he didn't receive the grateful welcome one would have expected from a mentor who would've otherwise been in mortal danger. Fearing for the students' lives, Hawks warned Jiro and Tokoyami to stay away from the battle, claiming it was no place for children. Tokoyami instantly shot back that he was just doing the job he'd been assigned, supporting the top heroes in case the battle with All For One reached a crucial moment. Realizing he'd been presumptuous and was underestimating Tokoyami, Hawks chided himself and, in the heat of battle, formally asked his student if he could lend some assistance as a full-fledged hero.
Their brief interaction followed a similar pattern to how Tokoyami's initial internship at Hawks' agency went. Having placed third in the Sports Festival, he was ecstatic to train with and learn from one of the top heroes firsthand. However, his experience was vastly different from what he imagined. Hawks' supersonic speed meant not even his Pro-Hero sidekicks could keep up with his work rate. And at Tokoyami's level then, all he and the other sidekicks could do was mop up crime scenes after Hawks had dealt with them.
Tokoyami resented this, and his resentment grew even deeper once he learnt Hawks had apparently picked him only because he wanted to speak with a student from Class 1-A. Tokoyami channeled his frustrations into strengthening himself and Dark Shadow, and was a completely different hero during his work study with Hawks. With his power-enhancing Black Abyss, the student could finally keep up with his mentor's speed.
This sudden improvement wasn't lost on Hawks, and he commended Tokoyami but also mentioned that he felt the young hero was limiting himself. He took Tokoyami on his first flight, and urged his fellow avian Quirk wielder to consider exploring the skies. That was the genesis of Tokoyami's Dark Fallen Angel.
Tokoyami and Hawks' relationship is another one that reinforces My Hero Academia's running theme of students surpassing their masters and the older generation. As they faced All For One, Hawks advised Tokoyami to take whatever initiative he felt was necessary, with the assurance that the Number 2 Hero would continue to back him up no matter what. Tokoyami evaded all the attacks directed at him, including a point-blank blast created with the combined might of All For One's Quirks. His evasive maneuvers allowed Jiro to fire off a perfectly timed Heartbeat Surround that aided Hawks in smashing the villain's helmet.
The heroes may have achieved their primary aim against All For One now, but they aren't yet in the clear. It's unlikely that All For One will be instantly incapacitated following his helmet's destruction, as he has proven to be extraordinarily tenacious. Tokoyami may yet have more opportunities to display even more of his strength. Given that his Ragnarok supermove has been more than effective against powerhouses like Re-Destro and Moonfish, Tokoyami might still be able to handle himself in the event of a surprise.