WARNING: The following contains spoilers for My Hero Academia Chapter 311, "Here We Go!!,” by Kohei Horikoshi, Caleb Cook and John Hunt, available now in English from Viz Media.
The pacing of the My Hero Academia manga shifts into high gear in Chapter #311, “Here We Go!!” as the top heroes find themselves under attack. Deku has been avoiding meeting up with his allies -- All Might and the Top Three -- to keep them out of harm's way, but it seems like the inevitable has finally happened: the chapter ends with All Might, Beast Jeanist, Hawks and Endeavor losing Deku’s GPS signal just as a bomb is thrown at their vehicles.
In the midst of the chaos, Deku is confronted by an assassin that he suspects has been sent by All For One, but after assessing the situation, it's unclear how true that claim is.
Many hints have been dropped as to how both sides are struggling in this post-anti-hero era, and it’s going to come down to who executes the first move successfully now. The remaining heroes are aware that All For One’s ultimate goal is to acquire One For All from Deku, but all of their searching for the League of Villains has left them empty-handed so far.
They are also blatantly using Deku as bait to lure All For One out, running the risk of losing him to one of the hundred or so escaped villains roaming freely. Their only advantage is the fact that Shigaraki has not yet allowed All For One to hijack his body, which is also causing some internal struggle within the League of Villains.
In terms of whether or not the other villains are working with All For One, there are two possibilities in the MHA manga that could shift the narrative. Based on the clues in Chapter #311, All For One has definitely made the first move by attacking All Might in his car, as well as halting the car with Best Jeanist, Endeavor and Hawks inside, with a bomb. That was clearly a collective effort to stop those key heroes at the same time, making the situation even more chaotic for Deku. All For One is desperate, given that he only has a short amount of time before his body deteriorates, and the timing of his attack lines up well with all the other confusion caused by those in society who have no faith in heroes.
As for the assassin who reveals herself to Deku, at first glance, she seems like a hired gun, but for some reason, there is a person unconscious behind her, in the shadows, without any arms. The unconscious person could have been the original hired assassin, and, for some reason, this new villain stopped them from attacking Deku. The fact that she refers to Deku as “Boy in Green” may only solidify this as she doesn’t even appear to know Deku’s name. If she was the hired gun, she would have known all the details about her mark, and how to stop him without retaliation.
Moreover, she also asks him to "come quietly" so he won't get hurt. The assassin’s merciful warning could be her way of telling Deku about All For One’s plan to abduct him. News travels fast in the villain world, and there are probably factions that are tied to All For One, but also possibly some that are tired of the old ways, and seek a new ruling system. She could have known about All For One’s plan to separate the heroes and decided to intervene before the League of Villains could get involved. Since she was in the same high-security prison cell as All For One, it’s safe to assume that she also held some sort of status in the villain world. Maybe she's even seeking to overthrow All For One. If true, these events could be teasing a potential hero/villain team-up to take down All For One and the League of Villains, especially in the wake of the previous war between the heroes and Shigaraki that didn’t end so well.
All For One’s seemingly impatient first move kicks off the plot for MHA's finale. It’s safe to assume that the heroes are not the only ones tired of the current status quo and seek some kind of resolution to it. All For One, meanwhile, might have just set himself up for a battle he was not anticipating with other villains, but knowing him, he’ll have another plan to handle any unnecessary retaliation.