Extended sustain duels and teamfight healing.
Durability and crowd control
Every 4s your next attack on a champion deals bonus damage, heals you, and permanently increases your health.
After taking damage from an enemy champion, the next 3 spells or attacks you receive deal less damage.
Start the game with extra health. After 4 takedowns, consume that health for adaptive AD or AP.
Increase your Tenacity and Slow Resistance for each summoner spell on cooldown. Immediately after casting a Summoner Spell, gain a larger burst of Tenacity and Slow Resistance for a moderate duration.
15-135 health (at levels 1-18) and +9% attack speed
Takedowns restore health and grant bonus gold.
Takedowns on enemies grant permanent Attack Speed.
Grasp on Darius allows you to efficiently out-trade your opponent in long duels, especially against tanks, with the combined healing from Grasp and [Q].
Bone Plating's excellent early game damage mitigation synergizes well with Darius' aggressive laning phase, allowing you to take aggressive trades to being snowballing your lane.
Chrysalis's early game health is great for taking aggressive trades during the lane. Once you are able to get the 4 kills/assists, the extra bit of Attack Damage is great for snowballing a lead.
Unflinching empowers your ability to stick to your your opponent to build Passive stacks, deal damage, and proc Grasp.
Triumph is fantastic for empowering Darius' reset nature playstyle. The massive heal can keep you alive in teamfights so that your able to get [R] resets.
The bonus Attack Speed from Alacrity allows you to build your passive stacks quickly so that you're able to execute your target as soon as possible with [R].