Darius Counter Tips
Darius E(Apprehend) can iniciate a deadly fight, so try to stay out of her range as much as possible.
Darius can do enormous damage in teamfights especially if he does multiple kill blow resets with his ultimate, denying it with a heal or shield may save your team from disaster.
Be aware of his passive which greatly increases the damage dealt from his ultimate.
Play defensively and bait him while waiting for him to make a bad move(Apprehend miss) then engage him and do the trade/kills.