Are you talking about Frontlines because they're useless in CC

It's very simple really. When you see a Dark Knight running at you, spread out and run away. If you can't make it use Guard. And use verticality to your advantage, like in Onsal at mid you can just drop down and suddenly no one is attacking you anymore.

It cannot be any simpler. See DRK, run away. That's it, that's really it. If you're someone with a CC you can be the hero and CC the DRK but on a job like DRG for example sorry to say you really should just run away.