A human Champion from Noxus in League of Legends usually played as an AP mid laner. She is one of the poster children of the series, and is best known for her dagger proficiency, spinning dagger throwing and stealthy assassin skills. She has a younger sister named Cassiopeia, and her missing father is General Marcus du Couteau.
She has a rivalry with Garen Crownguard. This relationship has been hinted at being more than just a rivalry.
Full title: Katarina du Couteau, the Sinister Blade
source: danbooru wiki