Irelia is a AD/AP hybrid champion that typically serves as the off-tank. She possesses decent damage output throughout the entire game and becomes fairly difficult to kill with the right build. Irelia is the first champion I bought when I started playing LoL. It's taken me long enough to make this guide but I hope you enjoy it.

Pros
+High damage output with some area effect damage (from ult).
+Can slow opponents and even stun if their health is higher.
+Very mobile on the battlefield.
+The beefiest of the assassins, serving as the off-tank.
+Very resilient to crowd control.


Cons
-Can be harassed early in lane, although has several ways to manage.
-Most of her damage is burst damage, since a full AD/attack speed build is impractical.
-Expensive to build.

Ionion Fervor


Each nearby enemy champion (to a maximum of three) reduces the effectiveness of Crowd Control on Irelia.

Ionion Fervor makes Irelia extremely hard to pin down and enables her to be a very efficient off-tank.
Bladesurge

Irelia dashes forward to strike her target for 20 / 50 / 80 / 110 / 140 (+1 per Attack Damage) physical damage. This applies on-hit effects. If it kills the target, Bladesurge's cooldown refreshes and refunds 35 Mana.

Irelia's Bladesurge is similar to Katarina's Shunpo or Jax's Leap Strike. The main difference is Irelia cannot use this ability on an allied unit. It gains effectiveness when she kills an enemy unit with it. The cool-down is eliminated and Irelia can jump to a new target.

Hiten Style

Irelia is skilled in the art of Hiten, passively giving her physical attacks health restoration. Activating Hiten Style adds true damage to her physical attacks for a short duration.

It's worth it to get an early point in Hiten Style to hold off on buying Hextech Gunblade until late game. Rank up this ability last unless you play on jungling, in which it becomes your priority.

Equilibrium Strike

Irelia's attack balances the scales, dealing damage and slowing the target. However, if the target has a higher Health % than Irelia, then the blow stuns the target instead.

Equilibrium Strike is a valuable move on offense and defense. It allows you to slow enemies to finish them off or change the tides of battle with a powerful stun. It can allow you to escape or even finish off a foe with greater health than you.

Transcendent Blades

Irelia summons four spirit blades which she can fling at her enemies. These blades deal physical damage to enemies that they pass through, siphoning life from them and healing Irelia.

Transcendent Blades heals Irelia for a large amount and has a relatively low cool-down. This ability allows Irelia to clear a minion wave incredibly fast. It also does massive damage in team fights if enemies are bunched up.

Flash

Flash is a must for almost every champ in competitive play. Combined with Bladesurge and Equilibrium Strike, Flash will allow for easy engages or escapes.
Ignite

Ignite will finish off those pesky champs your burst damage doesn't clean up.

Other Viable Skills
* Ghost allows Irelia to move around the battlefield but I feel isn't as necessary because of the speed my build provides.
* Exhaust is always great to go toe to toe with other AD or pin someone down but rushing Trinity Force and your Equilibrium Strike should be enough.
* Teleport...grab if no one else has.

I like to take 21 points in Offense as Irelia. Regardless of being hybrid, Irelia benefits most from this tree. I don't take Alacrity since most of Irelia's damage is burst and a little extra attack speed wont do much more. I put my remaining 9 points in Defense to increase my survivability and better perform the off-tank role. If you have an extremely squishy team it's viable to go 9/21/0 as well.

Early-game
Start off with a point in Bladesurge. Pick up Boots, 2 Health Potions, and a Mana Potion. Some people play Irelia as a jungler to avoid being harassed. This is a great way to play her but I'm not very experienced playing Irelia in this role. Be aware of your cooldowns early because Bladesurge is a large portion of your damage. Remember, some of its mana is refunded if it kills a target so focus on last-hitting minions. Once reaching level 6, your ult can be used to easily clear minions and you will start racking up minion kills extremely quickly. With your boots first you can avoid being harassed as much as use your Bladesurge to constantly move around. Begin picking up pieces to Trinity Force, which is what you will be building after your boots.

Mid-game
Finish off your Trinity Force and start working on building Guinsoo's Rageblade. You should complete both of these fairly early with the amount of minion kills you've picked up, as well as from champions slain. Your maxed-out Bladesurge allows you to finish off champions and pick up kills effectively. At this point, you will see players start putting out decent damage so I build my Warmog's Armor next. If you feel like you need a little more healing grab pieces to Hextech Gunblade first. When team fights begin, you want to be right up in the fray. Use Transcendent Blades early to do as much area damage as possible. Use Bladesurge and Equilibrium Strike to clean up enemies.

Late-game
Finish off Hextech Gunblade. I finish off with Guardian Angel to maximize my survivability. At this point you will be extremely hard to kill. Try to pick up the red-buff whenever you can still unless your AD carry needs it more. Late-game doesn't have as much to say since most of it is team positioning.

Core
* Boots of Swiftness- anyone who buys Mercury's Treads as Irelia is wrong. I go with more speed to ensure kills and to move around the battlefield.
* Trinity Force- hybrid heaven...this should be rushed to get that little bit of everything.
* Guinsoo's Rageblade- huge damage increase and the attack speed is great.
* Hextech Gunblade- everything a hybrid could want and gives you a lot of healing.

Optional Items
* Warmog's Armor- provides a great amount of health for your off-tank role.
* Guardian Angel- great for survival and allows you to finish enemies off.
* Spirit Visage- I love buying this item because not only do you have two moves that it benefits but it also affects your Hextech Gunblade. This is a great alternative to Warmog's Armor and MUCH MUCH cheaper.


If anyone has suggestions to other items I'm missing please leave a comment!

I'll be uploading some videos of highlights of my Irelia play once I have the time to edit them!

Irelia is a great all around champion. I'm open for adding anything you guys feel would improve the guide so feel free to leave constructive criticism in comments. If you find the guide helpful please vote me up! Thanks!