Maybe he was a B rank esper? Just very convientltly the guide does some werid things with his Chakra views that opens it.
Yes there's that as well that the guide does some shit that increases his ability. But in the early chapters they found out he resists reverse guiding and has unlimited whatever.
It mentioned in the story that when he receives over guiding or no guiding his ability amplify and become almost uncontrollable to the guide dude is the one keeping it under control while amplifying his abilities.
Idk if that's even mentioned seemed like a tl mistake actually, all he does is refuse it because of the side effect usually on them.
Why can't they just have an actual B rank esper be a B rank esper.....?
Now he's secretly overpowed and he didn't realise it yet. I just wish there ACTUALLY was a power difference romance bl, everything turns it to a op couple situation