A champion with this much mobility and CC should not be one-shotting people. Kayn's damage is way too high. His ult requires way too little set up to activate.
Every time I see a Kayn being played, he is legendary in no time. They can't ALL be good players.
You don't really understand how Kayn works if that's your opinion of him. Shadow assassin, which is the only form I would expect to 100-0 you, has only 1 slow. He does have a crap-ton of mobility though. Unlike some of the other assassins though, there are tells when he's coming for you. You can see a portal-like texture on the wall he's phasing in, which is also how he gets his move speed. Also, most of his damage comes from the first 3 seconds of a fight, plus another 3 if he ults. His passive will add an additional 12-44% (based on level) of his post-mitigation damage in magic damage. If you build armor, this will go down since it's post-mitigation. If you build mr on top of that, it'll do even less.
That much cc? you mean his skillshot slow in assassin form or his knock up in fighter form both of which have a delay so you can dodge it? That's kind of it there.
Most of the kayn's you see have probably played the hell out of him as he isn't easy to pick up at first.
Go tabi, zhonya. Rhast is very strong lategame in a team with tanks that help CC the enemy team, so he doesn't get bursted; Shadow is strong when fed and useless behind.
