Kai'Sa has a very good teamfight and laning phase kit. You have insane mobility and you are almost impossible to catch for your enemy. You are short range tho, so make sure to have ultimate, E or flash ready when teamfighting. You also have to oppotunity to assasinate enemies backline with your ultimate. This is why Kaisa is so strong

Doran's Blade: Doran's Blade may give less AD than Long Sword, but the HP makes you tankier and more able to survive all-ins, which is invaluable. Going Long Sword + 3 Health Potions would overall give you more sustain, but if you get all-in'd and either die or get zoned away from the minion wave then it's not worth it. It's also a more gold-efficient start as Doran's Blade is a super cost-effective item and you'll be spending 50 gold on pots rather than 150 gold, and eventually Doran's Blade's HP + lifesteal will outsustain those 2 HP pots anyway.

Stormrazor: Stormrazor is so good on Kai'Sa because it applies slow on the target you are hitting when Stormrazor is energized. This will make sure that you can get your passive off on the target. Also the attack speed from Stormrazor is great for getting your Q and E upgrades quicker


Berserker's Greaves: Well rounded boots with attack speed. Allways a good choice for almost every marksmen


Infinity Edge: Great crit item that provides alot of AD and increased critical strike damage. Giving you a large amount of critical strike chance and causing you to deal more critical damage on said critical strikes is very powerful.


Statikk Shiv: Great Zeal item choice / crit item when you really want some more waveclear on your team. You would like to get either Statikk Shiv or Phantom Dancer. I personally go for Phantom Dancer in most situations, since it provides great surviveability and Sivir has the greatest waveclear in the game anyways.


Mortal Reminder: You'll almost always want to build armor pen at this point in your build as enemies will have likely built a decent amount of armor. Whether to build Lord Dominik's Regards or Mortal Reminder depends on whether the enemies are generally tankier than you or not, and whether they have sustain or not. Mortal Reminder is generally the best of the two upgrades right now since there's so much healing in the game overall. Note that this item is useless if your enemy dont have tanks or a ton of healing ex. Vlad, Soraka, Mundo etc.


Bloodthirster: If you don't need the second life from a Guardian Angel then you'll almost always want lifesteal from either Mercurial Scimitar or The Bloodthirster in your build, and The Bloodthirster is IMO generally the best option for Twitch, since Spray and Pray tends to keep him well out of CC range. However, it's also situational and Mercurial Scimitar is something you'll very commonly have to buy instead anyway. An important thing to note is that there's a way to cancel knockups/knockbacks with Mercurial Scimitar, which involves using the cleanse during the CC. That alone won't get rid of it, but once you've cleansed, it'll allow you to cancel the knockback/knockup by using Flash, or any kind of dash. Demonstration by faker. So if you ever get caught by Dragon's Rage or Unstoppable Force while you have Flash up, with good enough reactions you can stay alive.


Guardian Angel: This is a very good item when you know you're going to have a hard time surviving team-fights. Only build it as a 5th or 6th item, though you can build Cloth Armor sooner if the armor is really that important. It replaces either The Bloodthirster or Lord Dominik's Regards, depending on which item is more important for you.


Maw of Malmortius: A very strong defensive item when you're taking heavy AP damage in fights. You start off with Hexdrinker and can build it earlier on then just sit on it until you reach 6 items before upgrading it to Maw of Malmortius if it's more important for you to finish the rest of your build. Generally this replaces Mercurial Scimitar/ The Bloodthirster, but it can replace your Last Whisper upgrade instead if you don't need armor penetration.


Phantom Dancer: is now a late game Zeal item that allows you to combine 25% critical strike chance and a defencive passive. It has the lifeline passive meaning when you reach a certain health threshold you'll gain a defencive shield. This also means it cannot stack with Maw of Malmortius or Hexdrinker. I suggest getting this item if you absolutely need the 100% crit chance or if you don't need the extra damage from shiv and would prefer an extra layer of defence.

I am actually a very active streamer on twitch and you can see me play alot of Sivir, Twitch and Kaisa at https://www.twitch.tv/lolpanu - Give me a follow to get a notification whenever i go live