This is a ridiculously overpowered Irelia build that I picked up during a match where I didn't get to choose my sexy sexy sweetie. I made a few tweaks on the purchase order and added malady, but I hope you all see how amazing it is.
As we stubborn Irelia players know, equilibrium strike is the fastest scaling skill damage wise in her arsenal. This build incorporates that knowledge, adds spell vamp, lifesteal, attack speed, damage, and ability power. It is hybrid, but not one of those fappy terrible hybrids.
Try it. Love it. Be the slaughter factory you have always dreamed of becoming.
Start with Early Sheen
If the game is still in play get whatever suits the match as your last. If you are able to maximize AP you can get Rabadons. I doubt a match will last this long
Then Prioritize in this order: Trancendent Blades whenever possible, then equilibrium strike, then hiten. Leave Bladesurge at Rank 1 until you can't upgrade the others.
I prefer Ignite and Flash. If you are feeling lucky, you can get teleport for lane flexibility and fast buying. I would sacrifice Ignite in this case, as late game you may need to get out fast.
This build's merits should be obvious, but I highly recommend you try it. AP, vamp, dmg, lifesteal, attack speed, burst. This is a synergistic build designed to exploit Irelia's uncommon durability, damage, and unpredictability.