The side character/boss character/soon to be fully playable character in her own game Silksong. Hornet gave eerie and critical messages during each encounter with the Knight before forcing him into boss fights. Team Cherry originally planned to make her playable in a short added DLC tacked onto the main game, but they decided to give Hornet her own fully playable game with her as the main character due to the overwhelming praise Hollow Knight recieved. Can't wait for that.