I don't think it's negation. You don't need to warn someone for that. Somehow I'm reminded with accelerator's vector power. I wonder if he's like that. Or a copycat or an amplifier. Hmm...
I don't know this vector power. Can you explain?
Copycat/amplifier has it's merit too but would he as an amplifier not just hurt himself more? Maybe if you combine it with a reflecting power thou... Amplify and reflect the power used against you. That's something you would warn people about not using their ability I guess.
That does make sense
The reference about vector power talks about the manipulation of the [Target] or [Direction] of some used ability or attack.
So if it result in being something between that thought, it could be some kind of Ability-Counter. Like the [Reflect] effect of Arlon Barrier. But tenfold stronger i guess...
So we noe know more about John's ability!
Like it have to be pretty damn high not only because of Isen's reaction but also because at his old school he was Rank 1 aka King!
And we now that his ability does something to the abilites of others when used. Since it is stated that you shouldn't use your ability when handling John.
I'm really curious about what it is! Still thinking about something like absorbtion or negation. (That would also explain the book his father wrote. Because then John would be the one "with power" in a world "full of cripples". When his power is so high all other people would be beneath him. Especially if he can absorb or negate the ability of others)