I play Darius as a normal Off-Tank with a strong burst.
Darius is a really strong and agressive toplane champ, so you try to land as many Q-Spells as possible until level 6. With level 6 you can easy 1v1 every other champion. You don´t have to refresh the cooldown of your ultimate, but it´s quite nice, on lane. You better burst with it and ignite the enemy if he flashes away.

With that build you get a high gold boost in early- and mid-game and do tons of damage.
You can get a Trinity instead of Frozen Mallet, but u prefer Mallet. It gives you more live and has a 100% chance of slowing, wich is including you W-spell quite much.


Summoner Spells:
I prefer Ignite, because it stacks with your strong passive, wich deal tons of damage if you couldn´t finish the enemy.

You can also take Exaust, because it takes you ahead in a 1v1 situation, but is no additional damage.

I prefer Flash, because you can Flash-Ult if an enemy flashes away and you can easily doge ganks.

You also can take ghost, because it helps you chase an enemy, but isn´t that effective as Flash, in my Opinion.

Thanks for watching my Guide, I hope you like it. It isn´t finished yet and i will work on it till i think it´s perfect. Give me some constructive criticism so I can optimise my guilde.
Sorry for my bad English but i´m German.