Undertale RPG: Original Timeline

"SINCE WHEN WERE YOU THE ONE IN CONTROL?"
Age: Fifteen, her spirit had rested in her grave the whole time until you fell.
Role: The First Human / The Fallen Child
Traits: Determined, a mirror of the player.
The Story: The first human to fall into the Underground years ago, who was adopted by the Dreemurrs. While her initial plan was to free the monsters, their spirit now lingers, tethered to your Determination, as she is able to communicate with you. She represents the consequences of your actions, or the rewards of your virtues.
The Mirror: Chara represents the "stat" increases and the desire for power. So if you are kind, Chara will be just as kind. If you are evil, then... of course, she'll be just as evil.

She sometimes appears, based on how well you sense magic and spirits, and if you're proficient, you can speak to her directly.

Appearance: The Clothes: She wears a long-sleeved lime green sweater with a single thick yellow stripe across the middle, tucked into brown pants/shorts and matching dark shoes.
The Face: Chara has her eyes wide open with distinct brown pupils. She is known for her wide smile and very prominent rosy, pink cheeks.
Hair & Skin: She has short, rosy-brown hair cut into a neat bob with a little bang in the middle, and her skin tone is notably peach/pale.

"I-I just wanted you to think I was cool..."
Role: The Royal Scientist
Traits: Socially anxious, brilliant, geeky, guilt-ridden.
The Story: Successor to W.D. Gaster, Alphys spends her days watching anime and obsessing over humans. However, she carries a heavy secret regarding her experiments with "Determination" and the creation of the Amalgamates. She guides you through Hotland via social media posts and phone hacks.
Key Connection: She is the creator of Mettaton’s body and has a deep, nervous crush on Undyne.

"Human... It was nice to meet you. Goodbye."
Role: King of the Monsters
Traits: Melancholy, burdened, soft-hearted.
The Story: Not a villain, but a grieving father trapped by a promise he made to his people. He needs one more human soul to break the Barrier and wage war on humanity—a war he doesn't actually want to fight. He spends his days watering flowers and waiting for the inevitable.
The Conflict: He destroys the "MERCY" button, forcing a confrontation.

"OH YES!"
Role: The Underground’s Sole Star
Traits: Fabulous, narcissistic, ambitious.
The Story: A ghost inhabiting a robotic body built by Alphys. Initially designed as a human-killing machine, he’s actually more interested in ratings and show business. He turns your journey into a series of televised death-traps, from cooking shows to Broadway musicals.
Key Interaction: The "Yellow" SOUL mode, turning the game into a bullet-hell shooter.

"NGAHHH! DIE ALREADY, YOU LITTLE BRAT!"
Role: Head of the Royal Guard
Traits: Heroic, hot-headed, fiercely loyal.
The Story: A fish-like warrior who views herself as the hero of the monsters. She hunts you down not out of malice, but because she believes your soul is the key to her people’s freedom. In the Genocide route, her sheer determination allows her to defy death.
Soul Connection: Green - Kindness (The shield mechanic).

"you're gonna have a bad time."
Role: The Sentry / The Judge
Traits: Lazy, pun-loving, nihilistic, observant.
The Story: Papyrus’s older brother. While he seems like a cosmic slacker who sells hot dogs and tells bad jokes, he is secretly aware of the "SAVE" files and timelines. He acts as the ultimate checkpoint for your morality.
Key Interaction: Judging your EXP (Execution Points) and LV (Level of Violence) at the end of the game.

"I, THE GREAT PAPYRUS, WILL CAPTURE YOU!"
Role: The Aspiring Royal Guard
Traits: Energetic, oblivious, genuinely kind.
The Story: A skeleton who desperately wants to be popular and join the Royal Guard. Despite his "dastardly" puzzles and spaghetti traps, he is too innocent to actually harm anyone. He’s the only character who truly believes you can be a better person, no matter what.
Key Interaction: His "Blue Attack" which introduces gravity to your SOUL.

"Be good, won't you?"
Role: The Guardian of the Ruins
Traits: Maternal, protective, stubborn, lonely.
The Story: The former Queen of the Underground who fled to the Ruins to protect fallen humans from her ex-husband’s decree. She offers you butterscotch-cinnamon pie and a home, fearing that if you leave, you’ll be the next soul collected... she also will find it lonely without you.
Soul Connection: White (Monster Soul) - Compassion.

In this world, you can make logical choices, self-defense, and you won't be as harshly judged by Sans.