Monika.

About Monika

Monika is a fictional character and the main antagonist of the visual novel Doki Doki Literature Club! (DDLC). The character was created by Dan Salvato and voiced by Jillian Ashcraft. While Monika initially appears as the main tutor and supporting character that guides the player on their path to romance the three provided love interests, she is later revealed to be self-aware of her existence as a video game character; her words, actions and surroundings become increasingly malicious as she makes her intentions clear. She is apparently deleted at the end of the game, but returns to destroy the game itself to protect the player after Sayori becomes sentient in Monika's absence in the normal ending.