What makes you suspect Vlad King?
I have some points here so let me put it together…
First of all, Chapter 21 said that All for one knew that All might has weaken. Which is understandable because he did put a hole on his stomach but..
The question is, how did he even know his weaken form?Chapter 92 stated that All for One knew that All Might has a ‘true form’ behind his muscular form.
The only people that knew of his weaken form is his detective friend, Tsukauchi, his successor Izuku, Gran Torino, U.A staff and principal.
We know by now, that the only way that All for one would get the information would be the ‘U.A staff’ because, one, they know of All Might’s weaken state or saw his true form and by that time, the only student that knew of his true form is Izuku. So there’s no way any student would have known that secret to pass it on to All for one.
Second. In Chapter 15, it is said that they don’t have information about the students.
But they got the information on the Class schedule where there’s also info that All Might will be in the USJ and as far as I can tell on the staff knew who was going to be there.
Third, In Chapter 70 before the summer camp arc. Aizawa said this.
The destination was changed and the only people that know of the location of the summer camp are the U.A staff and not the students.
The only U.A staff there are Aizawa and Vlad.
Fourth, in Chapter 214, Vlad being worried on Izuku’s newly developed quirk.
Which is true as you can see here.
Vs. on his reaction on this cases on Chapter 205
Chapter 202 where if you think about it, Tokoyami almost choked or could have died.
Even with all the destruction, all the aggressive kind of approach of Class 1-B on 1-A. Vlad didn’t react to much. He just brushed it off.
Lastly, in the BNHA Light Novel Volume 1, page 55.
Of all the teachers, Vlad was the only one without someone accompanying him and he was patrolling the school grounds. Which means no one knew what he is doing or monitoring him or what he was doing in the background.
If by chance, All for one knows the new development on Izuku such as the new quirk. Then that would lead to Vlad being the only one who knows this new development then thats just cementing it