This probably isn't the best way to build Irelia, but I found it to be half decent and it's good as the Mastery's and Runes for AP or AD Irelia are basically the same. This build is Irelia with CDR, AS and AP. With CDR, your W(Hiten style) can basically be doing 75 true damage nearly all of the time, as it will only have a cool-down of 3 seconds.Your w's passive with the attack speed helps your survivability and combined with Malady's unique passive, helps your physical attacks do 20 more magic damage. Q(Blade surge) will still do some damage, about 250 not including the 75 true damage that stacks with it. It'll also have a cooldown of 3.6 seconds.I basically just use it for farming and catching up to the enemy but it's still good for attacking. Your E(Equilibrium Strike) because of the AP will do a good amount of damage, with the full build doing about 437 damage every 4 seconds with a stun/slow effect. Your R(Transcendent Blades) will be awesome with the AP and CDR, doing 1.2k damage every 26 seconds and healing you roughly 300hp per champion you hit with all 4 blades. The burst damage of this will be about 1890 without the true damage and after 4 seconds, you'll be able to do another 700, again not including the true damage. The build is fairly squishy, but 1vs1 should always end good and its only in team fight you'll have to try and not get focused. Also, if it's just the burst damage you want, never mind Nashor's tooth, and go for Sword of the Divine, which adds another 30 armor pen. for the active and another 100 magic damage into every 4th attack for the passive,which stacks with malady. On a last note, the magic pen. is for your E, whcih does magic damage.