Hiya!
So just recently after playing some games, I was getting bored of the champions i already played with. Kat's shunpo just wasn't doing it for me anymore, and neither was mundo's cleaver, or rammus's taunt. I wanted something more! Exciting! Creative! I pondered the champions list with the small amount of ip i had in my pocket, looked carefully, and chose akali! One of the best purchases i have made champion wise. This is my first guide, my name is Valayntine, and welcome to Akali, Mark of the Nuke. (Warning: THIS IS JUST A GUIDE. Do not take anything i say here to complete heart, you are entitled to play akali HOWEVER YOU PLEASE. Tank akali? Be my guest. Stack 4 warmogs and atma's? I insist! This is simply a guide on my views of how i feel is an effective way to play akali.)

ONLY ONE OF THE MOST BADASS CHAMPS ASDHJGAJHDVMNBCASKCNM<X Dx
No but srsly, what's the deal with her?
Well let's get a little background out of the way about her moves and how they can be used differently.
This passive is so amazing, words cannot describe, but for the good of the build, i will attempt. It's a lot of words, but dont get confused, it's basically ap=extra auto attack dmg and ad=spell vamp. I have gotten my ip so high that i was hitting the opponent nexus for 400 and then my passive procing hitting it again for 450 for a grand total of 850 an auto attack.
This needs to renamed mark of the nuke. no joke. This is your main damage out put. Flinging this on a target before ulting to them then using an auto attack when close to burst the mark is an easy way to take out half health of an unsuspecting champion. Q+R+E is a good harassment when you get your ult. You will be doing severe chunks of their health and force them away from range of last hits and experience.
This has saved me so many times. Sometimes unfortunately some people are too afraid to initiate a team fight. Therefore, me having balls, i mark and ult into their team to start a team fight, and plop this down behind them to slow them if they choose to run. If i immediately get opened on i will run into this so i am no longer the focus target. they've wasted most of their burst leaving my ***** team to finish the job. This doesn't have to necessarily be used as a saver too. You can plop this in front of a target to stop them from running, or behind and enemy creep wave to intimidate them and deny them exp and last hits. + while in this bubble of awesome you recieve bonus mr and armor. This is a hat full of win.
This isn't my favorite move on akali, but it has it's moments to fill in when your mark or ult are on cd. It's great to last hit seeing as how it has a slightly larger then melee range and can hit multiple targets. The only problem is that spamming this along with your q will put yourself energy starved which is something you don't want. Imo, don't use this skill very much unless a team is running and you have rylais so you can slow their entire team, or you just need that extra hit to kill or take a last hit.
Ahh the chaser of akali. This is your deadly chaser. it doesnt cost ANY ENERGY so it won't energy starve you, it just costs shadow charges that you gain passively or from an assist/kill. This also makes akali amazing in team fights seeing as how if an enemy is slain, she gains an extra charge to continue putting out crazy bursts of dmg. I love this so much. THIS IS NOT ONLY OFFENSIVE BUT DEFENSIVE! *gasp* "Valayntine, how could this be possible!?" Well let me explain! Let's say you're carrying around a couple of wards (like i usually do) and suddenly you get ganked by swain and gangplank. Quickly you plop a ward on the opposite side of the wall into the wraiths and ult to them. Bam. Not only have you just put a ward in a key place of jungle, but you have successfully escaped a potential death on your part. You can also use this ult to dance around a team fight incase there is that one tryndamere or olaf that seems to enjoy chasing you while his team focuses someone else like our ad carry or something. This ult is what makes akali akali imo. It also procs rylais so it can slow as well.

Not that we know who we are talking about, I think i'll start off with summoner spells!
I always see people using flash, but to me, flash seems like one of the worst summoner spells to use.(for akali) When if first started playing akali, i found myself using flash to have to chase down enemise when they would run, and half to most of the time, i couldn't get the kill, thus wasting a summoner spell. Most people are carrying around a flash/ghost anyway, so for me to be using it to run seems quite pointless too, especially since i already can use my ulti to move to a mini in the jungle, or a creep on the lanes, and i can twilight shroud and stay stealthed until my team mates can get close enough to help me kill the mf chasing me. personally, exhaust works so much better. it decreases a targets dmg output which is great in a team fight, reduces their armor and mr, since i go for the mastery, and its a really short 3 min cd. If they flash, you have your ultimate to keep up with them unless they flash through a wall. I feel exhaust you can also use it to run away as well, and again it lowers dmg output so you can still be taking someone on if your at half health since you can heal yourself using your passive. I've been able to take 2v1s because of a well timed exhaust many a times. Imo, exhaust is a must

ignite is your swift kick in the ***. It's like "Oh well not only do i have an akali with full shadow charges on me, but now she's gonna ignite me for 20% of my health and the soraka's healing won't do ****. wahwahwah" Yes. I said 20%. people don't realize how much dmg ignite REALLY DOES. end game, this thing is a dot of death. It's also true dmg so if you find that one rammus who has no health but a **** load of mr, this ignite will be your friend.

(Possible other choices)
Teleport is a must in every 5v5. I feel if nobody has a teleport on your team, feel free to swap out your ignite for this bad boy. It gives great field control, can lead to a well put ward into a gank, and overall a very solid choice.
Not my favorite choices but in ranked games if you see they have a lot of cc (ex sion irelia taric etc.) then cleanse can turn their advantage into wasted moves.

I would'nt really reccomend any other summoner spells besides these. i find heal and fort useless, you can't use clarity, i PERSONALLY (dont get butt hurt flash fans) dont like flash on akali. clairvoyence is iffy, and only a few champs and players can really pull it off, and rally is a joke :P

On to masteries!
(I went with a 21/9/0)

[Offense]
Tier one: You're gonna wanna pick up cripple and archmage. This will give your exhaust even more of a deadly choice as it will increase the durationa as well as pierce through 10 mr and armor. the extra ap each level is a must. it may not be an insane amount, but every bit you can pick up counts

Tier two: You're gonna wanna pick up both alacrity and sorcery. Both help akali's dps significantly. Sorcery gives her mark and ult a shorter cooldown so you can mark dance combo quicker and alacritiy is to make sure you're auto attacks are gonna be fast enough to proc your mark each time you hit them with it so you won't have to be waiting that extra time to proc it.

Tier three: You're gonna wanna pick up burning embers, archaic knowledge, and sunder. Akali does rely on her auto attack as well as her spells, so picking up botht he penetration will help akali's dps rip through champions defenses. Burning embers will help early game by giving you an extra 10 ap after activating, so if you plan on ganking, be sure to use it before you use your mark.

Tier 4: pick up the only thing in tier four, brute force. This will give akali an extra 3 ad over other champions which will help with her early game passive to heal you, as well as make it easier to last hit early game

Tier 5: skip tier 5. you don't need crit damage since you're not specd into crit and you're not using rally

Tier 6: The bread winner of the offense tree. increasing your total damage output on spells AND melee attacks is a MUST have for akali. She excels in damage as it is, but this talent helps SO much end game, putting your damage at an advantage over most champs.
I put 9 into the defensive tree because i think we can all agree, when akali is outside of her twilight shroud, she's a little bit squishy to burst people like annie and other akalis

[Defense]
Tier 1: Pick up resistance and one point in hardiness. Since mr is harder to get in a larger amount then armor, it's only common sense if they are both going to give you 6 points, might as well get the mr since like i said mr is harder to get then armor. (ex: thornmail is 100 armor while force of nature is 76 mr.)

Tier 2: You're gonna wanna pick up evasion. This talent is SIMPLY AMAZING. Early game, mid game, end game, it helps SO MUCH. That extra 2% dodge gives you an unexpected survivability to auto attacks from champs, as well as creeps. I'm am completely in love with this talent

Tier 3: Your final talent point should go into nimbleness. This talent is crazy nice. Along with your runes, your dodge will give you an extra 10% movement speed. When ganking early game and your auto attack forces the creeps in your lane to target you, anytime you dodge one of those minis attack nimbleness will get refreshed, making it MUCH easier to early game gank since the 10% movement speed will allow you to chase down your opponent who only needs one last hit to finish off for first blood.

Runes runes runes. Btw. If you don't have runes, it's OK! Although runes do change your early-mid game play, it won't DRASTICALLY change your overall gameplay. Remember that most of this will come from your abaility to play, not the build, the build will just help you take right steps to find your perfect suited way to play her
: Magic penetetration will increase your damage ouptut over ap runes HANDS DOWN. The ap runes don't come close to a viable amount to = the piercing effect of spell pen runes
: As i explained again, magic pen > ap runes always. Theres + your marks sit you at a comfy 13.68 base magic pen + 15% from your talents, which should be enough to rip through most if not all of your enemies mr early game.
: I find that dodging an attack completely is better then having an extra (X) amount of health to take a hit. EVERY CHAMPION AUTO ATTACKS. Don't you ever forget this. No matter what, there will always come a point when an champion has to auto attack. These also come with great synergy to your nimbleness mastery allowing it to proc more often.
These runes give SO MUCH early game health, which will help your survivablity and intimidation GREATLY. You'll get to lane longer which will let you get more exp and last hits. imo, these are one of the most versitile quints. There is no champion that can really go wrong with picking these up

Hope you aren't too bored yet ;_; just a little more to go!
The items are there as a starting guide are your starters so you can get the spell vamp passive. I don't wanna go into much detail on items for one simple reason. No game should ever be the same. The items that i have provided i feel should be your base, but the last two slots should almost never be the same. Use those slots to build things like so you can counter that karthus/teemo, or so if their team is heavy ap, or if their team is too ad heavy. I don't like it when i see people building void staff when nobody on the opposing team has any mr whatsoever, or a mundo building mercury threads when their team has absolutely no cc. It makes me sick, because they could be getting better items but since they can't think, they just go mainstream and pick items they see in builds. My advice, be smart and pick items wisely, don't be a mainsteramer.

This was my first build! I hope my views and insight have been helpful. Feel free to leave constructive comments about how i have done, and if this build has helped you or not. I'm open to suggestions to how i could make my build better ^_^ Thanks for reading! This has been Valayntines guide, "Akali, Mark of the Nuke' baibai <3