Aggressive trades, tank shredding, and all-in duels.
Improved attacks and sustained damage
After a few seconds in combat, your first attack against a champion grants bonus AD and convert some of your damage to True Damage.
Takedowns restore health and grant bonus gold.
Takedowns on enemies grant permanent Attack Speed.
Deal 7% more damage to low health champions. Gain AD/AP after kills or assists.
Durability and crowd control
After taking damage from an enemy champion, the next 3 spells or attacks you receive deal less damage.
Gain permanent health when enemy minions or monsters die near you.
+9% Attack Speed
+5 Armor or 6 MR (match-up)
Conqueror on Irelia allows you to use your massive mobility to take extended trades/fights and dish out massive amounts of true damage.
Triumph is an all-around solid rune choice. In 2v2s and 2v1s, the extra healing can be enough to grant you the ability to sustain and move on to the next target.
The majority of Irelia's damage comes in the form of her Auto Attacks thanks to her [W]. Alacrity grants you the opportunity for an additional 1-2 autos when the enemy is stunned with [E].
If the enemy team has a ton of CC, Legend: Tenacity may be a better choice.
Coup De Grace allows Irelia to continue chipping away at her target until their life bar is fully depleted.
If you're planning to duel to the death a lot, Last Stand can be a vital option to hold your ground.
Bone Plating grants you early game damage mitigation helping you to sustain into an effective recall for Sheen.
Overgrowth's bonus HP makes you scale into a mid-game monster able to duel with anyone after your 2 item power-spike.