Human SOUL Magic System
(still no bullet pattern birthday cards...)
A Worldbuilding Exercise for Undertale/Deltarune
This isn't meant to be a system for well defined and tested mechanics, like what might appear in a utdr fangame or tabletop adaptation. Rather, think of these as the concepts for different human SOUL powers, and how a character would interact with them
This is my humble gift to the fan community. Feel free to use these SOUL powers as ideas to springboard off for anything related to Undertale and Deltarune; from fangames, to writing, to roleplaying
Human SOULs Change Your Perception
Every unique SOUL trait (indicated by color) alters the bearer's perception of the world. It changes how they understand the world on an almost instinctual level, and how they approach conflicts. These powers are based very loosely on various genres of games, and styles of gameplay. Naturally, from the perspective of the characters this is just how their world works, and they may not necessarily think of them as literal game mechanics
Powers
By default, every SOUL gets a "UI" sense appropriate to its genre, and a single power. Every SOUL also has a pair of "Actions" related to them, which further align with their power. "Advanced" powers are more dramatic, and resemble actual magic, but only rarely obtained, by entering the Underground or a Dark World. Theoretically, if a SOUL grows sufficiently powerful, it could even develop advanced powers outside of these "special rules" realms
Body and SOUL
Humans differ most prominently from monsters in both the physicality of their bodies, and the resilience of their SOULs. Monsters are deeply connected to their SOULs, such that if it were removed or the monster were to die, their SOUL would quickly begin to breakdown and eventually shatter. Shattering a monster's SOUL, or actively removing it from their body, is 100% lethal, and leads to the monster's corpse breaking down into dust. By contrast, human SOULs can persist outside the body, even after death. A human corpse will remain preserved so long as their SOUL persists. Should that SOUL ever shatter, their corpse will break down like a monster's, albeit extremely slowly through decomposition.
DT Extraction/Injection and SOUL experiments
There exist controversial experiments around the extraction or injection of Determination that have unique applications to human subjects. These individuals are able to have their SOULs physically removed, by themselves or with assistance. Through a concentration of Determination, the SOUL can be held or removed by hand/paw/appendage. This leads to physical trauma due to the overwhelming physicality of human bodies, even with the application of Determination to "soften" them
When a human's SOUL is removed, they immediately lose the SOUL's enhanced perception and special power(s), and cannot perform any related actions. Re-inserting the SOUL will restore access to these abilities. The long term effects of SOUL removal remain mostly unknown. If the SOUL is truly the culmination of one's being—the font of our compassion, the source of our will, the container of our "life force"—then what happens to a SOUL that has been removed for so long that it no longer resembles the human who bore it?
SOUL Traits and Powers
Genre: RPG
(Intuit stats and number changes, connect with friends, battle foes)
Actions: FIGHT, ACT
Power: Connect (Hear the inner monologues of nearby friendly or neutral characters)
Advanced:
Check (Learn how target creature describes itself. Focus to view a party member or friendly character via a cutscene shift)
Command (Order party members to perform various ACTs)
Control (Directly aid and compel party members)
Genre: Stealth
(Take your time, avoid unwanted attention, perceive threats)
Actions: HIDE, FLEE
Power: Scan (See the vision cones of anyone in your line of sight)
Advanced:
Sense (See vision cones without having line of sight. Know who is calm, searching, or on alert)
Stalk (Know when to take cover and when to follow. Make devastating sneak attacks)
Shadow (Environment lighting conveniently provides ideal hiding for you and friends)
Genre: Brawler
(Thrive in action-heavy or physical endeavors, do everything with Style)
Actions: LIFT, BREAK
Power: React (Briefly apply a slow down effect to everyone except you)
Advanced:
Rally (You and friends get Pumped Up!)
Race (Speed up your movement. Turn a confrontation into a chase)
Rumble (Beat up hordes of enemies, they won't attack all at once)
Genre: Precision
(Keeping rhythm comes naturally, surfaces support your weight easier, timing is everything)
Actions: JUMP, DASH
Power: Pulse (Feel the rhythm that others miss, follow your own tempo)
Advanced:
Parse (Know the timing needed to do something that requires movement)
Pirouette (Unleash the power of acrobatic dance to attack or confound)
Paradox (Break jump physics; double jump, coyote-time, infinite wall kicks)
Genre: Investigation
(The world is full of clues, search for them and be willing to try anything)
Actions: LOOK, USE
Power: Detect (See interactables, and characters you can talk to)
Advanced:
Deduct (Make leaps of logic others cannot. See contradictions and hidden similarities)
Distract (Use your cleverness to bullshit your way out of conflicts. Engage in battles of wit and rhetoric)
Defuse (Solve puzzles no matter how unintuitive the clues are. Delay a conflict to buy yourself and friends more time)
Genre: Social Building
(Socializing is your greatest strength, creativity comes to you easily)
Actions: TALK, CRAFT
Power: Intuition (Know what anyone wants when talking to them)
Advanced:
Identify (Find ingredients for crafting and learn recipes as you do. Locate the things people want)
Inspire (Help any character make something better)
Intermission (Make something that will change many lives, skipping ahead quickly with a montage sequence)
Genre: Explorer
(The Big Goal is what matters; go on journeys, navigate labyrinths, be implacable)
Actions: AIM, GUARD
Power: Target (Focus to see a lock-on reticle for any chosen character or object in your line of sight)
Advanced:
Track (An objective marker ensures you never lose sight of what you target. With practice, multiple markers can be followed)
Traverse (Find a way to reach your target by any means at your disposal)
Temper (Improve yourself, a friend, or a piece of gear when confronting your objective. If pushed to it, unleash righteous retribution)
















