Kayle is a minion till lvl 6, a weak champion till lvl 11, a strong champion that can make plays till lvl 15 and a hypercarry from lvl 16+. So, your main goal is to scale and reach the lategame where you will be a 1v9 hypercarry.

Pros

+ Hard Scaling
+ Burst Damage
+ Invulnerability
+ Snowballing
+ Strong teamfighting
+ Good poke against meelee champs after lvl6
+ Hypercarry with supportive potential (pretty unique)


Cons

- Depends on scaling
- Can get punished early
- Needs to count on teammates not to int early
- Squishy as hell
- Mana Hungry

This guide is made for top, mid and bot Kayle (with top> mid> bot imo). You can find success with Kayle support though, I personally love taking her support and aim for the late game, especially if I have a strong scailling ad carry with a safe lane like Senna, Xayah, Vayne, Ezreal or Kai'Sa on my team. I prefer to go aery for support though, to help the adc survive so we can both reach the desired late game successfully, so this guide is not for support.

The philosophy of the build is to go Hextech Gunblade early for more burst and utility since pre-lvl 6 you mainly fight with your Q+E and not with auto-attacks. When Kayle transitions to an autoattack hyper-carry (after lvl 11) you need to transition to your Nashor's Tooth. After that it's a mix of AP and attackspeed. If the team has a lot of tanks it is better for Kayle to build some AD so that she can shred more dmg with her auto-attacks so she needs Blade of the Ruined King. If the team has lifestealers like Dr. Mundo and Vladimir it's best for Kayle to build a Grevious Wound and dmg-over-time item like Morellonomicon and Liandry's Anguish. Mortal Reminder is not recommended for Kayle because even though Executioner's Calling is a very good early game buy against healers/lifestealrs the full item is not gold-efficient for her.

There are 4 main reasons why Omnistone is the best Rune for Kayle:

1. The inspiration path is very good for her because it helps her sustain her bad early game and scale into the mid/late game.
2. Kayle can utilize effectively all runes, allowing her to use Omnistone very sufficiently.
3. Omnistone is a strong late game rune since you can re-roll runes very fast and procc a rune much faster than you would with a classic rune setup.
4. The variety-style of the rune compliments Kayle's playstyle very well considering that Kayle is an AP Hypercarry with heals, shields and autoattacks/spells variety.


The Rune now has also a clever smart logic system that allows the rune to give the best rune option for certain situations, making it much more useful and practical in general.

Kayle is a unique late game Hyper-carry because at her current state she has less 1v9 potential than other late game Hypercarries like Vayne, Ryze, Jinx, Kai'Sa, Kassadin, Nasus, Veigar, Vladimir etc but she has the unique ability of beng a hypercarry that can also buff and sustain her teamates which makes the Kayle lategame teamfighting extremely strong.

Laning Phase

Kayle is just like Kassadin, Nasus or Veigar, you want to play safe and just wait for your spikes. Like these champs you also need to use your abilities early game to farm safely and effectively. That means you shouldn't really try to make plays in the lanig phase, but just focus on farming up, getting power spikes and then eventually ascend into true might. This is why you take E instead of Q at lvl 1. Eventhough Q is more effective for the early game since it can farm an poke as well you should avoid it at lvl 1 because it may force you to push the wave and end in a pretty exposed situation. You are one of the weakest champions in the early game so you should not worry about winning matchups pre-lvl 6 since you have like... none.

Mid game

Mid-game is a strange transition for Kayle. After lvl 6 Kayle gets ranged attacks and so she can start bullying meelee enemies, especially in the top lane. Still Kayle is not very strong yet, she just gets the tools to farm and poke easier so that she can approach lvl 11 and get more gold. She also gets her very strong ultimate that can save her from bad situations and get successful while also safer gangs. At lvls 11+ Kayle becomes a serious threat. You must definitely have Gunblade and Berserker Boots by then so that you can start building your Nashor's Tooth. WIth these items Kayle is pretty strong and has good lockdown, burst and dps. By now you can start grouping with your team and look for fights, or just chill in the sidelane getting more cs and xp, waiting to hit your lvl 16 powerspike. Remember, time is on your side!

Late game

When you reach lvl 16 you have reached your final form, you are at your biggest spike and you can finally bring judgement to your enemies. You can play as a splitpusher but you still need to know which fights to take. You can win against most champions except from some other late game Hypercarries that do more single-target dmg than you (you will struggle against a decent Kassadin for example). You are probably better than all of them in teamfights though. With your ulti and your max heal you can keep yourself and your teamates alive for a lot of time while you do a terrifying amount of dmg in burst and dps. By now you should most likely win the game if you and your team don't throw it somehow.