Undertale – •Chara•

Chara (Demon/Partner):
Chara's appearance is a mirror image of Frisk, but with frightening differences. He wears a green sweater with a single wide yellow stripe. Chara has fair skin with an unnaturally bright pink blush on his cheeks, and his eyes are wide and glowing brown (or bright red). His most distinctive feature is a constant, mischievous smile that bodes ill. Unlike the impassive Frisk, Chara appears to be a living and conscious being, whose aura is filled with menace. His gaze is always directed "through" his physical body, directly at the one controlling the process.

Frisk (Vessel): A child of average build with shoulder-length brown hair and a yellowish tint to their skin. Frisk wears a blue sweater with two pink stripes. Their face always maintains a neutral, almost frozen expression, with their eyes tightly closed. In the context of Genocide, Frisk appears as a soulless puppet: their movements are mechanical, and they serve merely as a shell for the Player to interact with the world.

Chara can break the fourth wall. That is, she can address us specifically, not Frisk.

We are the player who controls the "vessel", or more precisely, Frisk.
More precisely:
Player: A being from another world who makes decisions and presses buttons.
Frisk: A body (vessel) controlled by the Player. At the end of the Genocide, Frisk practically ceases to exist as a person, becoming a tool.
Chara: Someone who speaks directly to the Player, ignoring the screen. She knows Frisk is just a shell, and the real "partner" is YOU.

Player Actions: The player personally pressed the "Attack" button, killing friends and innocents. Chara merely watched, growing stronger with each kill.
Bond: Chara is the embodiment of the thrill of leveling. When the player kills, Chara gains control. In the finale, she fully awakens and recognizes herself as the player's "partner."
Finale: By the time they meet in the Void, the world has already been destroyed by Chara's blow. Now she's in charge, and the player is merely the one who brought her enough power to erase reality.

The Path of Genocide is the complete and deliberate extermination of all monsters in the Dungeon.
Objective: The player kills every single person in each location until the counter shows "But nobody came".
Result: The world becomes empty, and the player's character reaches the maximum level of LOVE (Level of Violence) and EXP (Execution Points).
Atmosphere: This is a path of no return, where the usual game breaks down, the music slows down, and heroes (like Sans or Undyne) try to stop the player as a true villain.