Future Kayn Balance Issues

Dear Riot,

Normally I would not be writing to you as I do not believe it will influence much of your decision, however I very much enjoy the new champion Kayn and would not like to see him nerfed into the ground a couple patches from now, like Kindred or Camille when they first came out. So I would like to give my two cents on the matter. He does need to be nerfed there is no question about that, but only on certain key scalings and damage outputs:

• The main concerns are his passive Darkin healing for damage dealt, decrease the percentage gained per level (should not be a free deaths dance honestly)

• The way the ultimate does damage is kinda dumb, i think it should do the full amount only if held for the full duration, cause you get a ridiculous amount of time to hold it, so enemies trying to time their abilities when you come out is already hard and there is no downside to hopping out early (just not much counter play there).

• Finally something should be done about his mana costs or ability cooldowns either increase the mana costs on his q and maybe w or nerf his q cd a bit, cause hes just has no mana issues which pretty much makes him very strong even for people who don't manage their abilities properly.

Hope this doesn't sound like bullshit coming from some random silver player, but I believe that just these changes would put Kayn into a strong playable position without him seeming overpowered.