We are squishier against AD assassins, so knowing our defensive options will be more important in season 10.[/h5]
[*] Guardian Angel has 40 armor, whereas Zhonya's Hourglass has 45.
[*] Phantom Dancer offers us a shield, and can be effective against 100-0 burst if paired with a Guardian Angel or Zhonya's.
[*] Phantom Dancer is typically not paired with a Zhonya's on Kai'Sa, as we are better off itemizing into either AD & Crit or AP & On-Hit.
[*] Zhonya's is generally more preferable on Kai'sa than a Guardian Angel for reasons other than the 5 extra armor.
[*] As it turns out, 40 - 45 armor isn't necessarily that helpful to begin with. We can still be bursted down if caught out of position.

Certain ADCs are able to use lethality items for themselves in certain situations. It is important to know if this includes the marksmen you main.[/h5]
[*] Kai'Sa is a hybrid champion, and magic damage does not apply lethality.
[*] Ezreal is a hybrid champion, but his Q deals physical damage, scales strongly with AD, and procs duskblade so he can occasionally build it.
[*] Kai'Sa deals some physical damage with her Q, autos, and Press The Attack early game, but that's basically it. Her evolved E isn't enough to refresh duskblade passive, but it can help continually apply it if you are near Fog of War.
[*] Lethality and %ArmorPen can slightly accentuate the other stat. Rageblade does offer this, in fairness.
[*] Duskblade does actually have more AD than Stormrazor now, for 300 less gold. This could make for a dramatically Q evolve without slowing down the E evolve, because that's a free dagger's worth of gold you just saved.
[*] Patch 9.24b may have made serrated dirk worth buying, even on Kai'sa. For the price of a B.F. Sword, you could have 30 AD, 10 lethality to make up the difference, a free health potion, and two control wards to sweeten the deal.
[*] Manamune build is underperforming a bit. I wouldn't knock on its lategame, but the early game just matters so much more with the new dragons. Duskblade could just be the best option for an early Q evolve these days, even if that's all it's good for.
[*] As it turns out, when you have an ability with strong hybrid scalings that deals physical damage, Duskblade into AP with a Deathcap hits for a lot.

If they can Burst you, Burst them First

[*] Marksmen succeed by whittling down their opponents from range before their opponent can get in range to damage them.
[*] Assassins succeed by getting in range to damage their targets before their targets have time to react.
[*] Mages succeed by chunking their opponents from range and backing away before they get kited out or bursted down.
[*] Kai'Sa is a Marksman, Assassin, and Mage hybrid. If you can't burst them, then kite them, and if you can't kite them, then burst them. Win the trades you can.