Undyne is a fish-like humanoid that is a cyborg. She has a crush on Alphys. She is an apprentice to Asgore. She attempts to kill the protaganist throughout Hotland.
When dared to lift the entire CORE as a kid, she succeeded but fell in the lava. Asgore, the royal scientist, took her in and repaired her severe burns with metal parts. Undyne thought this was cool and from then on saw Asgore as a father.
Undyne has been said to always attempt to fight her fans.
Undyne has a transformation,known as Undyne Umbra