Build 1: 15,100g
457 ms within 500 units of an enemy
5.856 ad with stacked rageblade (from movement)
1.91762592 attack speed
220.056 ad full stacked rageblade.
78.5 MR + 30 Mr stacks
300 health
136.4 ap damage
8% True damage
100 magic damage (active)
30% crit.
12% life steal
25% movement slowing resist (active)
20% Movement slowing (passive)
25% movement steal (active)
525 range.

Crit build: 16,700gold
285 ad
100% crit
30% cdr
1.6943860 attack speed
10% lifesteal
+60~140 shock magic damage
380 MS
Attacks become energized faster, now works on towers.
crit bonus 50%
700 range
taken from WildTurtles build

Upgrades
All three abilities are upgraded this way
dps on dummy (single target): 1650 dps


Crit build - WildTurtle: ER, IE, SS, Firecannon, Berzerker Grieves, Mercurial Scimitar
Icathian Rain
Supercharge.
Dps on dummy (single target) - 1000dps

BoRK is one of the best early trading items you can get. While she did get a buff of adding 25 units to her range, you still want this over any other item because she wants to trade. It is also one of her best items as she loves kite.

Second Core is PD. This has to be the best Zeal item for Kai'sai as she wants to charge in and also kite back. Her scaling with attack speed is what made this her second choice.

Last Item for "Core" is Boots of Swiftness. I picked that over Berserker Grieves as it feels better on her. Having that extra movement speed on her kit; it's surprising how much work they do.

you might be wondering where the Scepter came from. this actually does have amazing things for you. Permanent movement slows (tried Fist and hammer, both not as good. Second It gives Health. 300 health is nothing to scoff at. Third thing is that this should allow you to evolve your Void Seeker by hitting 100ap.

That being said This build is made in a vacuum. It feels good to play and build, and a lot of movement to adc and assassinate

PRECISION because shes scales very well off of attack speed. For that I go Triumph, Alacrity and Cutdown.
Keystone of Fleeting Footwork as you need all the life steal you can get.

For secondary runes I went celerity and Gathering Storm. I go Celerity because she loves movement speed. To get More AD because I'm building into speed; even better. Gathering Storm was chosen because it's a nice scaling rune.

There are two ways you can start using Icathian Rain or Void Seeker both are viable. You start with Icathian Rain if you think you can be the aggressor of the lane. The opponent is weaker than you at 1 and 2. If you choose Icathian Rain at level 1 pick up Supercharge second for a nasty all in. If you start Void Seeker this means you need to play safer like against Caitlyn. She out ranges you by miles but you have a source to get more pickup then you would otherwise. If you choose to go Void Seeker your next pickup will be Icathian Rain. Icathian Rain is your most damaging ability.

How you play her? play angles, I see this girl as the new troll. Shes an ADC but plays in the melee range. My build is 100% built around 1v5. so that means you should Dive right in, then kite anyone if anyone is chasing you. Figure out your escape routes is just as important as doing damage.

Laning with Kai'Sai is unique. She is compared to Vayne many times. But the only thing they have in common is Tumble and Supercharge, and they are both very good duelist's. Other than that Vayne actually has 25 more range than Kai'sai, and Vayne feels weaker in lane (as of 8.6). She feels really good not only because shes overtuned right now but because she has an ok way to clear waves. She doesn't need to by the Static Shiv to help her stay out of her own tower. Vayne relies heavily on her R. Kai'Sai doesn't need her R to all in. I only use Kai'Sais Ult if I'm giving chase or a cheese kill on their back lines to kill someone (in team fights).

How to player - fairly aggressively. No one on this patch (8.6) can straight out fight an all in against her. That being said, going against a Trist, Jinx or Cait can give you problems as their ranges are much more superior than Kai'Sai's. They usually cannot compete with your all in, but they have more poke on you so you can't all in. In this case farm. Kai'Sai is a great snowball champion, but she also scales really well late game.

You fell behind in the early game. If you are only a few cs(<15) and 1 or 2 deaths you can recover if you get a solid gank. If the drake is up and or the tower can topple, push in the wave after the gank and take one or both of the objectives.

Late game - If you followed this build you should be close to having all 3 abilities leveled up. There are two places you can be during a team fight. You can stand where normal adc's chill in the back of the group. Spamming your Void Seeker until the fight starts. You should be the last one in. If they change targets to you turn on your Supercharge and get out of there. find a bush to chill in for a moment the go back in.

If you are hyperfed you can do things like Flanking. For this to work either you and or your support needs to pink ward an area where you think the teamfight will happen. for this you usually want to be in enemy territory so you are right behind the squishies. Since they don't know where you are because of the pink you are able to target their squishies with a Void Seeker. When you Killer Instinct in, and make it rain Icathian style that Should pop the adc or apc. After that Supercharge your way out of there, again to get out of eyesite and then join back up with your team to mow them down.

Playing a losing match with Kai'Sai is very difficult. Her kit doesn't have any long range wave clear or cupcakes for the opponents to eat. If you get into a team fight thought, Bob. Watch the team go in, then go in yourself. Kai'Sai should be the target every time as you are the main dps. So you will need to dip in and out (bob in and out). Make sure to use Supercharge only to reset your opponents targets.

I have none I can comment about in other ADC's. She has such a high skill ceiling I can't really think of any 1v1's which I could mark as a definitive winner. Caitlyn, Jinx and Tristana each have a
"better" laning phase because of their long range. In a 2v2 environment That can easily be offset by Supports. The thing that will make you a great Kai'Sai adc and a bad one is the same as every other character that lanes: Knowing your lane Priority and have a brief understanding where their and you jungler is.

The champions I added to the list of VS's are either very good all in Zed and Kat or CC Gods.