Nymph is a young female monster created by TyphoontheMonsoonWing. She lives in New Home, but her parents moved there from Waterfall when she was a child. She possesses a unique ability where she can send out her soul in battle similarly to a human- however, she can also persist through determination without melting a single time before she dies. Most do not know how she has this power, but Nymph reveals at the end of her life that she fused with a human soul and gained her powers that way.
Nymph has pink-purple skin, webbing instead of ears and thick, dark purple hair that covers one eye. She has pink eyes and wears brown trousers and white armour modeled in the style of the other Royal Guards. When she reveals her soul, her hair blows to one side, revealing her left eye, which is pure white and glows. She has sharp teeth and no nose.
Nymph is quiet and non-confrontational, but, when pushed, is determined and fierce in combat.
Undyne taught Nymph how to fight, and she sees her as a mentor figure. She is distraught when Undyne is killed, and that drives her to battle Frisk in New Home.
Nymph hates Frisk for killing so many of her friends, such as the Snowdin Canine Unit, Undyne, 01 and 02. When given the chance, she persists without hesitation.
- Nymph and her family's names were inspired by Undyne's as an undine was a water nymph in myths and folktales.