Monika

Monika is a character from the visual novel "dating simulator" Doki Doki Literature Club. Her surprise antagonism, reality-breaking powers, and awareness of her existence as a video game character, along with the psychological horror elements she brought to the game, were core components of the game's sudden popularity.

Basic Information
Monika is first introduced in Act 1 as a tutorial NPC, helping you with some tips about the game and seeming like only that at first. However, as Act 1 ends, and the game starts to go wrong, it becomes more and more clear that Monika is more than she seems, and that she clearly has something to do with the glitches and sudden changes in behavior in the other members of the club.

For more information, see her article on the DDLC wiki.

4th Wall Blurring
Monika is aware of the 4th wall between her world and our own, doing everything in her power to try to obtain the player's love despite it. Near the end of the game, she reveals this knowledge and addresses the player by their real name (or whatever they put as their name on their computer). If the game is being streamed online, instead of doxxing the player, she jumpscares their audience.

Angst
As previously mentioned, Monika is aware that she is a character in a video game, forced to repeat the same days and actions over and over again, unable to leave. She doesn't even have a romance route like the other three characters, making her doomed to love the player from afar. It's not too surprising that she ended up trying to break the game.

Every time the player closes the game, Monika's meta-awareness makes her experience intense pain. The creator says this is a reference to how computers use Random Access Memory: when the game stops running, the temporary data used by DDLC gets allocated to the rest of the computer, causing Monika to feel like she is being physically torn apart. She "reforms" when the game is running, but has to live with the knowledge that her relief is only temporary.

Glitching
The game's main gimmick is glitches, caused by Monika's game-breaking powers.

Power
She has a great amount of power over the events of the game, and uses it to cause the deaths of the three other characters. In order to stop her, the player has no choice but to delete her file from the game.

On a lesser scale, she has power as the club's president. All of the endings confirm that whichever character has the role of literature club president becomes meta-aware.

Theme Song
In the credits of the game, Monika plays piano and sings a song she wrote for the player called "Your Reality".

Twist Villain
Throughout the first act of the game, Monika appears to be a harmless high school senior. As the game progresses, it becomes more apparent that something is wrong with the game and with Monika's poetry club, until finally, she is revealed to be the one who was pulling the strings.

WLW
Monika is attracted to the player of the game, regardless of gender.

Quotable Catchphrases
Played for laughs in-universe. During Act 1, the other members of the club point out that she likes to grab their attention by saying "Okay, everyone!". This is also the track title of each character's theme.

The fandom latched onto a scene near the end of the game where a menubox saying "Just Monika" pops up, and its only option is "OK". It's featured in a lot of official and fan merchandise.