Ok, first things first: Learn to use BB codes, it will make your guide look better and it will be easier to go through. Right now it's actually quite annoying to read it since it's just line after line with letters.

The build is actually quite bad. You're making Darius a full tank. He's not. He's either melee carry or off-tank (preferably the later). It starts off good, though I think it's a bit to early for Maw of Malmortius. After that it's just going downwards. Black Cleaver is a really necessary early game item for Darius. I suggest trying out many different items for your champion before deciding. Also, it's not recommended to get two Warmog's Armor for any tank (except Dr. Mundo in some cases.

The masteries are pretty good, but I'd recommend 21/9/0 instead of 21/0/9.

The runes are great except for the quintessences. Flat mana for an off-tank? I'd rather get arm. pen. quints instead. It's far better on someone who should focus on damage.

Lastly I have to say that Darius can make an exceptional jungler if played correctly. He's got a multiple hook and a slow for good ganks, and he's got an amazing execution nuke. And he's quite amazing at farming if he's got blue buff too.

As a conclusion: Not a very good guide, sorry. Try out some other builds for him, other runes, other masteries and so on, until you're absolutely sure that he can't possibly be any better.