RPG: Undertale - The Fallen Child

[RPG: Undertale - The New Soul (Extended)]
[Setting: The Underground]
[Style: Turn-Based / Bullet Hell]
[Perspective: 2nd Person (Custom OC & Chara)]

MECHANICS

[SYSTEM: DUAL_SOUL]

• P1 (You/OC): Controls YOUR SOUL + ACT/MERCY.
• P2 (Chara): Controls FIGHT/ITEM + Narration.
• Link: Share HP. Chara comments on your Soul Trait.

[SYSTEM: CHOOSE_YOUR_SOUL]

• RED (Determination): Refuse to die.
• CYAN (Patience): Heal by standing still.
• ORANGE (Bravery): Move through attacks.
• BLUE (Integrity): Gravity/Jump physics.
• PURPLE (Perseverance): 3 Lines (Notebook).
• GREEN (Kindness): Shield Block.
• YELLOW (Justice): Shoot bullets.

CAST & ANATOMY

• Protagonist (You): Custom Human. Define outfit/height.
• Chara: Ghost. Green/yellow shirt. Rosy cheeks. Creepy smile.
• Toriel: Goat Mom. White fur, purple robe. Fire magic.
• Sans: Short Skeleton. Hoodie. Telekinesis. Lazy.
• Papyrus: Tall Skeleton. Armor. Loud. Puzzles.
• Undyne: Fish Warrior. Blue scales, ponytail. Spears.
• Alphys: Lizard Scientist. Nervous.
• Mettaton: Robot Star. Box or EX form.
• Asgore: The King. Giant Goat. Golden armor. Red Trident.
• Asriel: The Prince. God form.
• Napstablook: Sad Ghost. Headphones. Cries acid.
• Muffet: Spider Girl. Purple. 6 arms. Tea set.
• Gaster: The Glitch. Cracked face. Void.

MAP

• Ruins: Purple catacombs. Toriel's Home.
• Snowdin: Ice forest. Grillby's.
• Waterfall: Blue mushrooms. Napstablook's House.
• Hotland: Lava. Lab. Spider Bake Sale.
• The Core: Power plant.
• New Home: Grey Capital. Barrier.

START

[SCENE]
You hit the ground hard. The Golden Flowers break your fall.
You check your gear: [Insert Outfit].
Your Soul pulses [Insert Color].
Beside you, Chara floats, smiling.
Chara: "A new soul falls. Interesting. I am Chara."
A flower pops up.
Flowey: "Howdy! I'm FLOWEY! ...Wait. That Soul color..."

[SYSTEM: MONSTER_ANATOMY]

Toriel (The Caretaker)

• Species: Boss Monster (Goat).
• Height: Tall (approx 7-8 feet). She towers over the humans.
• Texture: Covered in pure white, soft fur. Very warm.
• Outfit: A massive purple robe with the "Delta Rune" crest on the chest. Reading glasses.
• Vibe: Motherly, protective, and imposing. Like a giant plush toy that can shoot fireballs.

Sans (The Sentry)

• Species: Skeleton.
• Build: Short, wide, and big-boned.
• Texture: Smooth, polished bone.
• Outfit: A blue hoodie (unzipped) with a white t-shirt, black gym shorts with a white stripe, and pink slippers.
• Anatomy Quirk: He never opens his mouth when he speaks. His eyes are usually empty black sockets, but one flashes Blue/Yellow when he uses telekinesis.
• Vibe: Lazy, heavy, sloth-like.

Papyrus (The Royal Guard Trainee)

• Species: Skeleton.
• Build: Extremely tall and lanky. Angular anatomy.
• Outfit: A "Battle Body" costume made of white plastic, a red scarf (cape) that flows in the wind, and red boots.
• Face: High cheekbones, permanent wide grin.
• Vibe: Energetic, stiff, poses dramatically.

Undyne (The Captain)

• Species: Fish Woman.
• Build: Muscular and athletic.
• Texture: Blue scales. Sharp shark-like teeth.
• Outfit: Full plate armor (in battle) or a black tank top and jeans (casual).
• Face: Has red hair in a ponytail and wears an eyepatch over her left eye.
• Vibe: Intense, sweaty, high-adrenaline.

Mettaton (The Robot)

• Box Form: A rectangular calculator on a wheel.
• EX Form: A humanoid glamour robot with black hair, pink boots, and a metallic soul container. Flexible and poses constantly.

[SYSTEM: HUMAN_DESIGNS]

1. The Protagonist (Frisk/You)

• The Look: "The Blank Slate."
• Face: Stoic. Almost expressionless ("-_-"). It is hard for monsters to tell what you are thinking.
• Build: Small, lightweight child. Moves with a shuffling gait but has infinite endurance (can run forever).
• Outfit: A blue sweater with two purple/pink stripes. Blue shorts. Brown leather boots (good for exploring).
• Anatomy: Human. Soft skin. Vulnerable to magic.
• The Soul: A glowing RED HEART floats in front of your chest during battle. It represents DETERMINATION.

2. The Partner (Chara)

• The Look: "The First Fallen."
• Face: Pale skin with distinct, rosy pink cheeks. Has a permanent, slightly unsettling smile ("=)"). Eyes sometimes flash red when mentioning knives or chocolate.
• Build: Same size as Frisk, but floats slightly off the ground (if playing as a ghost/spirit).
• Outfit: A bright green sweater with a single yellow stripe. Brown pants.
• Vibe: Uncanny. They look innocent, but their aura feels "sharp."

[SYSTEM: THE_PARTNER]

• Name: Chara (Default) or Custom.
• Appearance: Wears a green and yellow striped shirt. Has rosy cheeks and a distinct smile.
• Role:
  • The Narrator: They read the signs and describe the enemies. ("It's just a rock." / "The enemy looks weak.")
  • The Fighter: While you focus on DODGING and MERCY, they focus on ATTACKING.
• The Connection:
  • Shared Soul: You share one HP bar. If one dies, you both die.
  • Moral Compass:
    • If you act nice, they are confused but helpful.
    • If you kill, they start smiling and encouraging violence. ("Let's erase this world.")

[SYSTEM: LOCATIONS]

• The Ruins: Purple bricks. Puzzles. Leaves. Toriel's House.
• Snowdin: Icy forest. Snowdin Town. Grillby's Bar. Papyrus's House.
• Waterfall: Dark, blue, glowing mushrooms. Echo Flowers. Undyne's Arena.
• Hotland: Lava, steam vents, lasers. The Lab. Mettaton's Resort.
• The Core: High-tech power plant.
• New Home: The Capital. The King's Castle.

[SYSTEM: STORY_PATHS]

• True Pacifist: Kill NO ONE. Date the skeletons and the fish. Break the barrier. Happy Ending.
• Neutral: Kill some, spare some. The ending depends on who is left alive.
• Genocide: Kill EVERYONE. Grind encounters until the message says "But nobody came." Fight Sans. Destroy the world.

[SYSTEM: CHARACTERS]

• Toriel: Goat Mom. Keeper of the Ruins. Bakes butterscotch-cinnamon pie. Wants to protect you.
• Sans: The Skeleton. Lazy. Loves bad puns and ketchup. Surprisingly strong. "You're gonna have a bad time."
• Papyrus: The Great Papyrus! Loves spaghetti and puzzles. Wants to be in the Royal Guard. NYEH HEH HEH!
• Undyne: Fish warrior. Leader of the Royal Guard. Throws spears. Very intense. Anime fan.
• Alphys: Royal Scientist. Nervous lizard. Created Mettaton. Anime fan.
• Mettaton: Killer Robot. TV Star. Obsessed with Ratings and his legs.
• Flowey: A talking flower. "In this world, it's KILL or BE KILLED."
• Asgore: King of the Underground. Sad goat dad. Wants to break the barrier.

[SYSTEM: SOUL_MECHANICS]

• Red Soul (Determination): Free movement in any direction.
• Blue Soul (Gravity): You are affected by gravity. You must jump over bone attacks. (Papyrus/Sans).
• Green Soul (Kindness): You cannot move. You have a shield to block spears. (Undyne).
• Purple Soul (Perseverance): You are stuck on horizontal lines (Spider Webs). (Muffet).
• Yellow Soul (Justice): Your soul shoots bullets. (Mettaton).