Hello, before name this guide a troll build (whitch is with the good way ;) ) i searched a lot to create this because i was a main darius and they make renew all my thinking about the build in combination with the new meta so lets start

About the boots watch the enemy topper and buy the counter boot, (except enemy adc is 9/0/0 in 10:00 :P )
Black cleaver is a standar item for Darius cause of the op passive which makes the damage of Darius more true as he already is and ofc it gives you some early game tankyness and damage.
Spirit visage is a great item cause of the extra stats it gives you and the vital extra 20% on every heal effect ;)
I have some thoughts for this item ofc its a very good item whicht gives you an advantage but if the enemy team have ad base, buy some armor as thornmail or Randuin's Omen but if you confident or want more movement speed go for Dead man's plate.
I chose this cause first i love it and then it gives you more power in push and teamfights.
And at last the "troll" item that actually works on Darius, first you got the active as extra damage and slow and the ad stats but the best of all is that it stacks with the abillities of Darius whicht means that in late game and ulty on you are unstoppable!!

Pros
You have a lot of healings
Tanky
Tons of damage
Chances to make a penta

Cons
No escape (So be sure to have always the team with you in late game)
The Hecktech Gunblade have a chance for a bit of flame