Darius Needs a Nerf and if you Don't Understand That you Should Stop Playing LoL
He gets free damage just for doing what every character needs to do. He deals true damage with an ult has a twitch passive that stacks just as well does more damage and increases his abilities. He can tower dive like its nothing with 0 items because he's tanky and deals adc damage. If you don't think Darius is op and riot are the best game developers in the world go fuck yourself.

Step 2: Kite
Step 3: If you cant kite, run when he has 3 stacks on you.
Step 4: Cant run? Build qss
Step 5: Build 
passive from 50% to 30% [zombie-brand-clap]
early to counter his Q., and dorans shield to counter his bleed.
try to dodge his q TOWARDS him so you wont get a bleed stack/damage/he heals. engage on him relatively early (lv5ish) and try to get ganks, smart people can easily 2v1 him, he has no escapes. and dont dive him. and for the love of god DONT TRY TO AUTOATTACK HIM TO DEATH AT EARLY LEVELS. olaf does well against him. he is actually decently balanced RN.