Irelia Build Guide by the chaos bringer 00
Not Updated For Current Season
This guide has not yet been updated for the current season. Please keep this in mind while reading. You can see the most recently updated guides on the browse guides page.
WORK ON PROGRESS FOR SEASON 4. GUIDE WILL BE UP-TO-DATE UNTIL NEXT WEEK (NEED TIME TO CHECK OUT NEW STUFF). CHEAT SHEET UPDATE: OPTIMAL SET-UP RIGHT NOW. STAY AROUND.
Hello guys and welcome to my Irelia guide. Irelia is a very strong champion with a very strong kit. Thanks to her kit, Irelia can carry a game hard and at the same time be a great anti-carry during team fights. I dress Irelia with an "on-hit" style of build, with which I am able to maximize her late game power and not her mid game as most guys do (ΙΜΟ)
In this guide, you will find all the important information to play Irelia and succeed with her. In general terms it may seem similar to other guides, but I guarantee you I haven't copied nothing from anyone. All this precious experience comes from hours of practice with her and of course by watching a lot of streams. I don't opt for the top because I know that my guide is not that good but I would be glad to help the members of this on-line gaming society learn how to play Irelia. Also through this guide I can even improve my gameplay with her through constructive feedback. So I really really beg you to leave constructive feedback like the first few guys that visited my guide who really made me reconsider my options and improve myself and this guide. If you leave constructive feedback I promise to do so to one of your guides as long as I can :)
Pros and Cons
Safe blind pick
All kinds of damage
Very nice late game
Both good burst and sustained damage
Can adapt to all situations
Deals TONS of damage while being very tanky
Weak early game/lane phase
Die early on = disaster
Susceptible to early pushing
Susceptible to early ganks
Ultimate is meeeeh
"Better nerf Irelia" exists for a reason
Hard to calculate when e stuns or slows
As Irelia you must survive the lane phase and strategically build your items to fit the game you are playing. The 21 points in the defense tree are just the way to achieve this. The rest 9 points are a simple personal preference. That is to say, you can put the 9 in the utility tree or split them for a 1-21-8 set-up which is also very efficient.
So now let's have an in-depth look to what every mastery does :)
: The bonus 5 AD/AP are awesome during lane phase. Augment damage on Auto-attacks, Bladesurge and Equilibrium Strike.
: Attack Speed is great on Irelia for getting extra Auto-attacks while Hiten Style is activated.
: Why not have some bonus Attack Damage since I don't build a lot of it ?
- Weapon Expertise : Armor penetration is a nice addition to have, especially since everyone runs 13 armor.
: More health for every level you have. Why not have a bonus 108 at level 18. Helps against bursts of damage.
: These are essential for laning so why not. If you are against AD then put 3 in
and 1 in
but if you are against AP, switch them :0
: 2 less damage may not seem like a lot, but it's good early on against harassment. It also allows chances to make epic escapes with 1 or 2 hp xD
: With Zephyr plus the masteries we will see later on, this mastery almost makes a door through all slows
: A nice durability bonus early on against harassment or minion aggro.
: This mastery plus
makes you extremely durable against early harassment.
: This is what I was referred to in the description of
above. This adds to your being almost immune to CC. Also it is the reason why the defense tree is just op on Irelia.
: 2 points in this plus the other health masteries mean 142 bonus hp at level 18. Think also that the 2,75 % multiplies with the rest of your HP too which let's say is 3500. 3500 + 138 = 3638. 3638 * 2,75 / 100 = 100. 100 + 3638 = 3738 which means almost 240 hp bonus from just 2 points
: As Irelia you must go in the back lines of the enemy team so people will be usually around you. So why not have another 5 bonus Armor/Magic Resistance.
- Honor Guard : When you are in the middle of the chaos of a team-fight such damage reduction offered by one single point is really good.
Greater Mark of Attack Damage
Greater Seal of Armor
Greater Glyph of Scaling Magic Resist
Greater Quintessence of Attack Damage
9x Greater Mark of Attack Damage
Extra attack damage for better last-hitting since Irelia must farm all day long in order to activate beast mode.
S U B S T I T U T E:
9x Greater Mark of Attack Speed
Attack Speed is extremely important for landing some extra AA enhanced with Hiten Style. However before picking these up, take into consideration that you are already building much of it.
S E A L S:
9x Greater Seal of Armor
Armor is essential on top lane for countering physical damage and last longer under early minion aggro.
S U B S T I T U T E:
9x Greater Seal of Scaling Health
Only if the enemy team is full of freaking burst damage. However, I think that you can already resist to that.
G L Y P H S:
9x Greater Glyph of Scaling Magic Resist
Magic Resistance per level is oriented for late game when you are against a somewhat dangerous AP carry which can be your first/second priority.
S U B S T I T U T E:
9x Greater Glyph of Magic Resist
If you are against a magical damage Top laner. For example, Elise, Rumble, Vladimir
Q U I N T S:
9x Greater Quintessence of Attack Damage
For extra last hitting and damage output.
S U B S T I T U T E:
9x Greater Quintessence of Movement Speed
Movement speed is important on Irelia. You don't have any escapes and in case of ganks Movement speed and maybe an Equilibrium Strike is your chance for survival so these are also good.
Flash is a must. You can get closer to the enemies, Flash over a wall, juke the opponent and of course escape ganks. Flash + Equilibrium Strike is the most typical way to initiate a fight.
Ignite against an easy lane opponent. I suggest this especially on Solo Q. At level 9 with maximum number of Auto-attacks enhanced by Hiten Style you can deal much true damage with it. Not to count the extra physical and magical damage you can do ;)
OTHER SUMMONER SPELLS: - -
Substitutes of Flash
Ghost is more of a tank oriented ghost spell. Worked better on the old Irelia but as I've said it can be still used.
Substitutes of Ignite
Teleport is much better for arranged ranked games and for against the laners you have to struggle in order to win. It offers dragon/baron control and can prevent dives and/or a turret being destroyed. Also thanks to the much attackspeed you build, Irelia is a very good split-pusher, so abuse that.
Exhaust is very useful against high physical damage teams. It wins trades, saves your life, and grants kills :)
What it does:
Reduces the duration of stuns, slows, taunts, fears, snares, immobilizes, blinds and silences for each nearby enemy champion. 1 Champion: 10%, 2 Champions: 25%, 3 Champions: 40%
This plus Tenacious plus Mercury's Treads' tenacity make you immune to all CC in team fights and can grant you a chance to live when you get ganked. This is why Irelia is such a great anti-carry: destroying any squishy target without getting cc'ed. In my opinion it is one of the main reasons why Irelia is considered mobile and scary :D
What it does:
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.
This can deal pretty huge burst. It procs Sheen and Hiten Style which means free pass to freaking huge damage. A nice combo would be: activate Hiten Style--> Auto-attack --> Bladesurge --> Auto-attack: Bladesurge resets the auto attack timer so this combo is a good way to scare off opponents. You can last hit under your tower with it or even prevent some enemy minions from dying by your own. However don't use it on every single minions 'cause then bb mana. I will describe some nice combos with it on a chapter later.
What it does:
Irelia is skilled in the art of Hiten, passively giving her physical attacks 5 / 7 / 9 / 11 / 13 health restoration. Activating Hiten Style doubles the health restoration to 10 / 14 / 18 / 22 / 26 and adds 15 / 30 / 45 / 60 / 75 true damage to her physical attacks for 6 seconds.
One of the strongest abilities in the game. @ lvl 9 (and under normal circumstances) you can win all trades. Bladesurge and Transcendent Blades proc it so they heal you equally. Remember that although the true damage does not apply on turrets, your AA will heal you. Generally it's the skill that you should rely on. That's also why you must build AS on Irelia.
What it does:
Irelia's attack balances the scales, dealing 80 / 130 / 180 / 230 / 280 (+50% of ability power) damage and slowing the target by 60% for 1 / 1.25 / 1.5 / 1.75 / 2 second(s). However, if the target has a higher Health % than Irelia, then the blow stuns the target for 1 / 1.25 / 1.5 / 1.75 / 2 second(s) instead.
This skill is extremely strong. It can really turn the tables to a diving opponent. With this you can also get more dangerous with your Hiten Style damage. You can also harass a champion with it. However you need to practise with this so that you can land, almost of every time a stun instead of a slow. I should point out here too that the stun "happens" not only when the HP% of yours is lower than your foe's but also when you have the same % of HP for example when you are both at maximum health. Knowing when it stuns or slows makes a good Irelia player.
What it does:
Irelia summons 4 spirit blades which she can fling at her enemies. These blades deal 80 / 120 / 160 (+50% of ability power) (+0.6 per bonus attack damage) physical damage to enemies that they pass through, and she heals for 25% of that damage vs champions and 10% vs minions.
Nice poke during lane phase. You can clear minions quickly and buy you some time for split pushing or ganking. Also procs Hiten Style which means super heal. It does mediocre damage though. Learning how to aim with this can give you some kills or even bonus assissts during a fight.
- Take Equilibrium Strike at level 1. It will be extremely useful in case a level 1 team-fight occurs or when the enemy top-laner is one of these you have to work to win or if they have a level 2 ganking jungler (ex. Lee Sin)
- Take Bladesurge at level 2 if everything is fine or if your lane is getting pushed.
- Take Hiten Style at levels 2,3 if you are pushing your lane and then take Bladesurge at level 4
GENERAL SKILL ORDER RULES!!!
- Max Hiten Style by level 9 --> Best thing to do as Irelia
- Max Equilibrium Strike by level 13 --> Because CC is important in team-fights
- Max Bladesurge by level 18 --> It's only a gap-closer and an initiation tool. You don't rely on it for your damage output.
- Take points of Transcendent Blades at levels 6, 11, 16
- When an enemy jungler is coming from behind you, use Bladesurge to reach him and get further away from your enemy laner.
- You can use this skill to also jump walls
- Use this skill only to farm minions you cannot reach with an autoattack in time in lane
- Use this move on a low hp minion to juke enemies
- Use this skill from a brush so you can make your jukes more successful
- Bladesurge + Trinity Force + Hiten Style = 1 dead full hp caster minion
- Use this skill to close the gap between you and an enemy by killing a nearby creep so you can initiate with your Equilibrium Strike. This way, you will have your Bladesurge up in case the enemy is able to outrun you or use a gap closer/Flash to escape you
- Great last hitting tool at turret
- Use Hiten Style at turret to farm minions if you do not have the autoattack damage to last hit properly
- Use Hiten in order to heal up more. You heal even when you attack buildings
Sometimes, you want to prolong the use of Hiten Style against certain enemies. Against say an Akali or Fiora, you want to prolong your use of Hiten Style until they have blown their "Twilight Shroud" or "Parried" skill
- Use this skill to greatly amplify your damage with true damage
- Bladesurge does trues damage too if you activate it.[/list
- In 1v1 battles, use only when the stun is procced. The 1-2 second stun will actually make the difference between a dead or escaped opponent
- Circumstance when you can use Equilibrium Strike will be when you are simply harassing with E+AA
- Bait enemies with Equilibrium Strike. When you are of lower health percentage, you can still kill someone because a 1-2 second stun is huge.
If you are getting turret dived, don't be afraid to use your Equilibrium Strike on the enemy. This will make the enemy panic and hesitate whether they want to dedicate and continue diving you or run away. This hesitation can also net you free kills.
- When getting ganked, you can use this skill to escape with the stun.
- When you are far overextended and getting ganked by the enemy, walk into the brush and use Equilibrium Strike - this guarantees the enemy cannot land a skill on you before you strike them with your crowd control.
- Flash + Equilibrium Strike = INITIATION MECHANISM
- Only use this skill in 1v1 situations to heal up and do damage
- As a last resort, you can use her ultimate to heal up a random creep wave. (Last resort only- this is a waste of your mana and cooldown otherwise)
- When using this in a 1v1 fight, try positioning yourself in a way where this can also heal off of minions in addition to the enemy.
- Use this skill to manipulate minions with your Bladesurge. If you are trying to make big plays and Bladesurge won't kill a minion upon cast, you can use her ultimate to lower the health of enemy minions so that you may have your Bladesurge up in the scenario where your enemy runs away from you or uses a gap closer/Flash to escape.
- Push waves with Transcendent Blades when you are going to gank other lane, or any other reasons where you want to push your wave.
- Hit multiple enemies in a teamfight to heal up and get assissts
+ +Sight Ward
Currently the best starting items at least for top lane. However if they have a level 2 ganker (ex. Lee Sin, Shaco) I tend to pick up +3x
With this start plus the sustain from Hiten Style you can stay in lane for even and just farm and farm and farm. It is quite a strong start since people will have small or no amount of Armor Penetration early on.
It is not as strong as it used to be. If you are running MS quints then do not ever buy this at spawn. However if you're not running the MS quints, be sure to buy this only if you somehow know that your lane is gonna be easy as cake.
VS AD LANER:
or +(possibly)Situational Early Item
Since season 3 there are a lot less items for Irelia to take midgame. The core, Phage still stands and should always be taken before midgame. In most laning phases, farming your Phage will be your main goal. After your starting item you will want to invest into a Phage as early as possible unless you need a Doran's item. If you dont get a phage and invest in other areas you wont have any chasing power which Irelia relies on to make plays, which means your kill potential in lane will be heavily amplified. Remember that this build heavily focuses on attack speed from runes and items, and Bladesurge also opens up ways for more proccs. The health it provides is also incredibly strong in laning phase since you will far more often win duels or survive ganks with it.Tier 1 boots will always be core in laning phase to be able to harass, trade and escape from opponents. Berserker's greaves however shouldnt be taken before you have a fair amount of both attack damage and survivability. Keep in mind that attack speed is weak without attack damage since you wont have any burst, and its weak without survivability since you wont have any time to actually dish out the bonus attacks before you're forced to fall back. Ninja tabi is strong season 3 especially since armor penetration is far more common for toplaners, but i prefer just going a cloth armor or doran's shield to make up for it. Ninja tabi can be picked relatively early in lane. I pick Stinger after phage against AD opponents instead of Wit's End because its very cheap while still giving the same attack speed as Wit's End. Again, keep in mind that attack speed is weak without survivability or attack damage. Don't go Stinger before Phage, and never buy Zephyr this early. I used to always go Wit's End in lane but since it was nerfed I have replaced it with Stinger for AD matchups.
VS AP LANER:
or +(possibly)Situational Early Item
I go Wit's End against hybrid or AP matchups for obvious reasons. It gives a big amount of damage and survivability while benefiting from both bladesurge and attack speed. You can go for Wit's End before Phage against low mobility champions like Warwick. But against Rumble, Vladimir and Kennen etc Phage is needed. I never pick Mercury's Treads (anymore) because Zephyr is one of my core items. Additionally, Wit's End is better to rush in lane than Mercury's Treads in all AP matchups.
SITUATIONAL EARLY ITEMS:
Doran's Shield is a very effective start against some AD champions but I don't like building it later in lane unless I'm forced to. Later lane is where Irelia really starts dominating trades so i prefer having some more damage or utility.
Doran's Blades are often used as a core item for Irelia but I wouldn't put it as that since Phage gives the same kinds of stats. It is however, very strong early on combined with attack speed or armor penetration. There are several situations where a Doran's Blade can be bought, the most obvious one being where you need some damage to shut down lategame characters. The most common case through tournament play is when you need some burst on your Bladesurge and autoattacks against someone like AD Nidalee, Jayce or Jax who all have steroids/jumps/knockbacks to keep you from dealing a lot of sustained damage.
The Brutalizer should only be taken if your going for a more AD oriented build with Trinity Force. But the cooldown reduction combined with the amazing damage output can win you lanes against squishy opponents. I like going a few Doran's Blades or Doran's Shields if i use this item because it has 0 survivability into it. Build it into The Black Cleaver after Trinity Force, in case you keep it.
These are the items that you get in 99.9999999....% if not at 100% of your games. They offer survivability but the main thing is AS which is extremely important for dealing huge damage with Hiten Style. As far as the boots are concerned, I complete them after Phage.
6th item (situational):
The last item is directly relevant to your needs and to your role in the team. You can fill the last spot up with anything from the "SITUATIONAL ITEMS".
When:If the enemy team consists of many people with more than 3k health, grab this. It also provides sustain and a damaging active.
A truly damage item. Get this if you need to sustain your self. When: if you are sure to get all the stacks this is a must.
This has become very good after the changes. Greatly enhances your damage output and provides some health. It gives you the set-up of an AD caster I usually get this when the enemy team has a decent amount of armor or if i have kept The Brutalizer.
A must when there are more than 3 opponents having extreme armor. You have true damage but you still rely on your physical too.
Fo' teh lulz. Ridiculous damage but not a serious item to consider on Irelia. Build this only if you are really ahead and want to win asap.
Just a ridiculous amount of health. I like this very much. Build this against team comps with huge burst damage or teams with hybrid damage.
This goes very well paired with a Frozen Mallet (if you build it instead of a Trinity Force) and ofc with Warmog's Armor. Gives a nice amount of armor and the critical chance isn't bad at all.
Grab this is the enemy team relies mostly on auto-attacks or consists of many AD champions. Plus you can spam abilities all day long :)
In the occasion that the enemy team relies heavily on auto-attacks, get this item! Be warned, you need a decent amount of HP to buy this item before seeing a difference in enemy damage. Also be careful because this item is countered by lifesteal.
You are extremely durable against CC but this is always an option against teams with suppress. Skarner and Warwick are the reasons why I usually build this item.
When you are tanky enough you can always build this for extra HP, CDR and an initiation means.
Poor expendable enemy top-laner
Akali is a bit like you but better in assassinating. She can do damage extremely quickly and can be a pain in the *** if you don't play carefully. Play defensively against her because if she manages to delay your snowball, she has won the lane. Due to her freaking stealth your trade power reduces. However with an Oracle's Elixir you should have not a difficult time. Mind she is not very good at huge team fights where you naturally excel so use that ;)
Cho'Gath is a tanky top-laner but you have true damage so go to hell big dinosaur. Remember he can do great burst because of [[Feast] and can cut your trade in 2 pieces with knock-ups and silence. He has huge CDs though so abuse that :) It is more of a farm lane so farm ASAP to 9 and never let him go out of control.
Unfortunately this is one of the guys YOU HAVE TO WORK AGAINST. Darius is an excellent at dueling, tanky, AD caster. He can harass you quite easily and his passive adds to the damage from the trades. His Crippling Strike is simply extremely fearsome because it cuts AS by a lot and you need that. Try to trade with him if you know that his ultimate is down. Also try make him spam abilities because he has mana issues. This is one of the guys that you have to build Phage before Stinger.
Diana is a fascinating champion. She is in the same category as Fizz and they are only two of a kind. Her early game sucks more than Irelia's so abuse this. If you bait her shield and then don't let it refresh you can destroy her. With a few early ganks she will become useless as she will either die or go back because she has no escape.
Elise is tanky and somewhat good at assassinating. She can escape easily from your trade and wait till most of your Hiten Style effect is passed. She can easily kill guys below 25% so beware of her gap-closer. She is considered by many to be a real headache for melee tanky top laners but honestly, she hasn't given to me much trouble.
Seems like a mirror lane. You both snowball hard and letting anyone of you farm would result in disaster for the other. Try to bait her Riposte and deny her farm and you're golden. You might wanna build Ninja Tabi to deny her damage early on. Try not to get baited by her defensive disengage, Blade Waltz especially when you are going to unleash your full combo.
Same as Diana but he has escape and a much more enervating ultimate. Try to avoid his fish and save up your Bladesurge for when he does his juggling thing. Remember also that he can minimize the healing from Hiten Style so don't expect trading with him to be as easy as against others.
Ok mister tank Galio. As I've said he is tanky but will mostly build MR. Whith a stun you could cancel his ultimate but because your's is not on-hit you might have some trouble cancelling it. He can be extremely annoying in lane as he heals from the damage he takes. With careful play you won't have problem. Don't make an effort to go toe 2 toe with him he is hard. Better call your jungler
You stack armor so that's it. Deny him the farm from Parrrley and remember that he has his fruit salad to get out of your stun.
He can zone you extremely well, so you might have a hard time against him. Also you shouldn't ever underestimate his burst. Try to trade with him when his spin is on CD. Don't feel horrified though, you are way better later on.
You are both weak on lane phase you both rock late game. Try to shut him down and beware of ganks because he can cooperate with jungler really well. He is generally tanky but you have true damage so it's easier than it looks. Remember of his sustain when you are going to fight him.
DIFFICULTY: DEPENDS ON SKILL LEVEL
The difficulty level is pretty obvious. Unfortunately I don't have a lot of info on how to play this mirror match because I've never met an Irelia when I play as Irelia. You can follow though the general advice that you follow when you play vs Irelia as any other top-laner. Watch the minions around you for any possible Q-E combos, and do not trade with her when Hiten Style is activated. The Irelia that kills first the other Irelia is undoubtedly the winner of the lane so ask your jungler's help and always buy wards to avoid enemy ganks.
DIFFICULTY: HARD LIKE CATCHING MEWTO WITHOUT MASTERBALL
Ok. Ok. KILL THIS MOTHERF@CKER WITH GANKS BEFORE 6. IF YOU DIE TO HIM THERE IS NO WAY TO COME BACK. ONCE 6 HE WILL PUSH THE **** OUT OF YOU TO YOUR TOWER AND HE WILL DIVE/HARASS YOU WITH HIS E. I WOULD RECOMMEND TAKING Teleport FOR GOING BACK AND RETURNING QUICKLY. HOWEVER YOU ROCK MORE LATE GAME. EVEN IF HE HAS OUTFARMED YOU (NORMAL RATE OF 20-30 CS) BUT YOU MANAGED TO SURVIVE WITHOUT A DEATH THEN GG YOU ARE STILL AHEAD. OH YEAH I FORGOT THIS IS ONE OF THE GUY THAT YOU REALLY HAVE TO WORK AND PUT YOUR BEST IN ORDER TO WIN.
End of chapter more lanes coming :)
Last hit all day long. Irelia is pretty weak early-on so you can only play safe. Your creep score is extremely important. I use the 16 minute mark when I play in top-lane and my high score is 160 creeps in 16 minutes with Jayce. With Irelia it's about 132 creeps in 16 minutes. Last hitting is important cause that way you push your lane as little as possible. The only reason you would push your lane is after you have killed an opponent and you go gank another lane, or if you want to go shop. You should also zone your opponent as far as you are able to 1v1 him. Irelia is under normal circumstances able to trade efficiently after 5 level. At 9 level when you are at peak lane strength you should zone the opponent hard. Zoning means between the enemy and the minion wave so that they lose experience and gold. Also during the lane phase you must have extreme map awareness. Ok so an ally didn't call "ss" or "mia". You cannot rely on them forever. You have to be based on your map awareness in order not to have problems.
Mid game is the hardest part of the game. Many players stop farming because they think: "Ok I have farmed a lot and have some items, let's go push lanes, team-fight and get dragon/baron". All of these are right. Bringing down turrets, who give map control to the enemy, team-fighting and getting dragon/baron, are all things that happen during mid game. However you must not stop farming. Most of the gold during this period is given to AD carries so that they can have a powerful late game and carry their teams to victory. However if they do not go and clear all the minions from a wave why shouldn't you? Also you should not stop buying wards. They offer the great map control you need in many places such as dragon, baron and of course in the enemy jungle. Also before completing the objectives of mid-game that we have discussed above I suggest that you group-up with your teammates. As a result there won't be any chance of you being outnumbered in team-fights.
Keep constant vision of the Baron!!! Acquiring the Baron Buff, winning team-fights and taking down buildings are the main objectives of late game. Other objectives are now trivial. Always proceed to something with your team. Never be alone!!! Since in this phase of the game most players are fully built a 4v5 fight (where you are the 4) is almost sure to be a fatal fail.
THE ULTIMATE GOAL OF A GAME ISN'T TO GET KILLS ALTHOUGH IT IS A WAY TO WIN. THE ULTIMATE GOAL IS TO DESTROY THE NEXUS. PROLONGING THE GAME CAN RESULT TO A COMEBACK FROM EITHER TEAM AND THEN, THE TEAM WITH THE BEST TEAM COMPOSITION WILL WIN. WHEN YOU HAVE A CHANCE TO DESTROY THE NEXUS AND WIN THE GAME, ABUSE IT. FOLLOWING THIS TACTIC I ONCE WON 20 GAMES IN A ROW (5 OF WHICH WERE RANKED).
Let's consider a 5v5 fight with teams that follow the meta: AD Carry, Support, AP carry, Jungler, Bruiser/Tank solo top.
Now your primary target in a fight like this is one of these guys:
Yes you got that right the AD Carry.
If you manage to survive after this effort the next priority is the AP carry.
The target sequence is ADC>APC>ANYONE ELSE
You can initiate but if you have one of these guys: I would suggest that they initiate. Irelia works best with another tank in the team. For example if you have an Amumu in jungle let him initiate and then go insta-burst the poor enemy adc. If you are the one to initiate, save your bladesurge for their Flash. Don't Bladesurge the person you want to kill because your stun won't work. Doing a stun right on the enemy carry is crucial for the outcome of the teamfight.
If their APC is more dangerous than their ADC I would suggest to do your CC on the APC so that your team has a chance and then destroy the ADC.
There are of course the general rules. If they focus you --> Guardian Angel + ARMOR ITEM/MAGIC RESIST ITEM/HEALTH ITEM. Armor for physical damage teams, magic resist for magical damage foes, health vs great burst, true damage.
If they don't focus you, LET'S BUILD TEH DAMAGES!!!
BUT WHAT IF THE ENEMY ADC IS ON VACATION FOR FARMING?
Then... just take down the next squishiest/high damage target which is normally the enemy APC.
I am certain that this won't reach the top not even the top 5. Once the 20 first votes are made the guide will get punched by all the members that don't really understand the meta and will leave comments as "NO DAMAGE AT ALL" or "THIS BUILD SUCKS I CAN'T WIN". If this doesn't happen this guide might be forgotten like other guides. Anyway I will update this regularly, to make it more detailed and of course complete the huge match-up section. The "cheat sheet" constantly change based on what works and what doesn't so if I find something more efficient I will update my guide :)
Hope you liked the guide and I expect you to press that green button. However if you choose to press the red one then pls, in your comments say why you did this.