post #1286775

"See that heart? That is your SOUL, the very culmination of your being!"

An interpretation of the soul, unique to the videogame Undertale, and its spinoff, Deltarune. A human soul takes the form of a heart, colored according to the personality of its owner. The soul of a boss monster takes the form of a white, upside-down heart.

A soul is the culmination of a person's entire being, and as such, essentially is the person that it belongs to. The soul is also a source of significant magical power - in particular, human souls are extremely powerful, and can be used to perform various incredible feats, such as creating magical barriers, firing energy blasts, seeing and speaking to people from well beyond line of sight, recovering from death, and even resetting time.

Monsters have the unique ability to steal souls. While the soul of a typical monster is instantly destroyed upon death (preventing its capture) the souls of humans and boss monsters are stronger, and can survive outside the body for a few seconds before shattering. During that window of time, a monster can steal a soul from a recently deceased human or boss monster and use its power as their own, resulting in an exponential increase in power.

• Undertale wikia page
• Deltarune wikia page