Hello I am Kingemon333 from the Oceanic pro server scene, I am currently sitting at Gold V and playing mid with my team CLG.OCE. I have figured out a way to never die playing as Akali, and now I will teach you how to play Akali and always win!

Pros:

Crazy sustain (thus "never die")

Insane late game scaling

1v5 God

Decent burst damage

Cons:

Ignite kills you

Heal and Barrier will allow you to survive for longer, they are basically bonus health which you can use whenever you want (if they are off cooldown). You don't really need it late game because your items and passive will give you so much sustain anyways but these items can surprise your opponents in early fights, help you win 1v1s or survive 5 man ganks.

Many would say that flash will help you escape more often, but this is simply not true, because your ult is basically a better flash on a shorter cooldown and resets on kill/assist.

Passive - Twin Disciplines
This passive is easily one of the best stacking passives of all time. It is one of the main reasons of your crazy sustain late game. It turns your bonus AD into spell vamp as well as making your auto attacks stronger.

Q - Mark of the Assassin
Just use it to farm early. If you auto attack an enemy hit with this ability, they will take bonus damage. This will help you burst, it is also single target so it will heal you a lot due to your spell vamp.

W - Twilight Shroud
This makes you invisible, gives you some movement speed and also slows enemies down. You can use this early game to hide and escape, and use it late game to wait out your cooldowns. When your cooldowns for your other abilities are done, you can use them again to heal you from all the spell vamp.

E - Crescent Slash
AOE spell, remember to use it on many minions so you can heal a lot. Nothing much more to say.

R - Shadow Dance
This is a crazy ability. You can use it to chase people down, even if they try to flash to escape. Its got a relatively short cooldown and you can store up to 3 charges at a time, and you also gain a charge whenever you get a kill or assist. You can also use it to escape by dashing to jungle camps over walls.

Your basic combo is Q>R>E>auto attack>Q>R/auto attack
When you have at least 2 charges of your ult, you can use this combo, use Q on the enemy champion, and back off so they won't be scared off, when they walk back to get CS, ult onto them, use E to get some damage off and auto attack them to proc your Q. If they are not dead yet, Q them again (it should be off cooldown), dash to them if they are out of range for your auto attack and auto attack them again to kill. Use your cutlass/gunblade active to slow them down if you need to, it can be useful if you don't have your ult up as you can slow them down and catch up to them.

This is the build sequence if you want to never die. All of these items give you sustain. I will explain how to use the active items correctly. I will also show you the mathematics behind these items later in the guide.
CDR boots combined with your CDR runes will help you spam faster late game and thus give you more potential healing.

These runes gives you early game sustain with the armor and spell vamp as well as giving you late game power with the stacking attack damage and cooldown reduction.

Taking 9 points in defense will give you some survivability, I opt to not use 30 or 21 points in defense since your items already make you so tanky and give you so much healing/sustain that you really won't need the extra defenses masteries

21 points in the utility tree gives you many many benefits. You get extra income from the gold per 5 points which will allow you to get to your late game full build faster. Cooldown reduction on your summoner spells and active items will help you use your defensive summoner spells more and your active items more often. And of course, the 3% bonus lifesteal and spell vamp will contribute to your total sustain.

Late game, you will have so much sustain, you can just go into the enemy team 1v5. Just spam everything whenever they are off cooldown and try to use hydra and your E when you are at the center of the enemy team to ensure you can hit as many enemies as you can and maximus your heal.

Upon initial observations, you can clearly see the raw healing powers of this build. In this section, I will show you just how much sustain this build will grant you with the power of mathematics.

Lifesteal:
3% from masteries
10% from Gunblade
12% from Hydra
20% from Bloodthirster
+20% of total from Spirit Visage
45*1.2=54% total lifesteal

Spell vamp:
3% from masteries
6% from runes
15% from Will of the Ancients
20% from Gunblade
Your passive gives you 6% + 1% per 6 bonus AD spellvamp
AD you get at level 18: 22 (runes) + 80 + 75 + 40 = 217 bonus AD
217/6= 36%
42% (6+36) from passive
+20% bonus from Spirit visage
86*1.2=103% total spell vamp

WOW! This is why you will never die!

With this guide you should never die late game, just play safe until you get your core items and you can basically 1v5 faceroll enemy teams with your crazy 54% lifesteal and 103% spell vamp. No matter if you hit the enemies with an ability or your auto attack you will heal a lot of damage back. Just remember to use your abilities whenever they are off cooldown and the enemy team should not be able to kill you.
GL, HF :)