Using death threats such as "kys", or prompting people to commit harmful actions to themselves or others with vulgar language is immature, and unacceptable.
Nowhere in League of Legends should anyone be seeing these types of words when playing games. Inciting people to do things that they shouldn't be inclined to do should never, EVER be seen in this game.
These types of words and actions deprives players of their motivation and determination to play, and may also encourage them to commit self-harm and/or worse actions. As a frequent soloQ player, I always remind myself that whoever I'm playing with is still human, as I am, and is still subject to toxic behavior and actions, like I am.
If you ever see somebody using these types of words, be sure to report them at the end of the game, and take a screenshot of what they said.
Always remember that people are human and aren't perfect, and remember that you don't know what is going on in other people's lives.
"_Those who cannot remember the past are condemned to repeat it."_