It's only that... It's not really something just anyone can interfere with. I'd be glad for more help. [technically] But...
[a sigh, and then, explaining] They, the Noah, are superhumans who get their power from something called Dark Matter. Dark Matter can only really be combatted by its opposing force, Innocence, which is what we Exorcists use to fight. [he lifts his left hand in demonstration]
But... there's no point in fighting them, anyway. Killing them would only make things worse.