When you get 1-shot by Kai'sa's mark....

her w gets bufffed the more marks she has on the target, so, at 4 marks, plus w = you get bursted

not many people know that. and that is why her meta buids are pure ap

even with ad i think it can burst, since her ad scaling on w is higher

also magic resist is a joke right now

A good hunter never lets her quarry escape.

Seriously though, you say "one shot" but roughly half of the damage you're taking is from her W impacting and that leads to a bigger pop on her passive, which gets most of its scaling through missing HP. If it's just her, perhaps you should have been more careful about letting her get the jump on you.

I think the mark applies in the tick after the damage that triggers it. So the w chunks you, then the passive calculates its %missingHP off of that.

https://www.youtube.com/watch?v=I5GdyAkHCTE

you mean this