Undyne is a fish monster. She likes anime, especially if it involves fighting with giant swords. She also regularly trains at Aaron's gym.
Undyne is a lot calmer than her Undertale counterpart. She has a strong sense of justice, and because of this she also acts as the judge. She usually sees boss monsters as a threat, but due to an agreement with Metta, she doesn't attack them unless absolutely necessary.
Powers and Abilities
Undyne is known to be one of the strongest monsters. She also has the hardest boss battle in the game, known to be harder than both Undyne the Undying and Sans from Undertale.
During her battle, Undyne can summon Temmie attacks, showing a connection between her and the former royal scientist. Undyne also keeps her signature spear attacks from Undertale.
Undyne has mostly the same appearance as in Undertale except that she doesn't have an eyepatch. She is wearing a black hoodie, blue shorts and red shoes.
Undyne and Alphys have a close relationship. The two usually enjoy watching anime together. Undyne cares about Alphys a lot and will hate Asriel if he kills Alphys.
Undyne encountered Metta at one point when she was training outside. During their meeting, Metta asked Undyne to not attack any boss monsters that she met.
Undyne doesn't seem to trust Asriel and keeps an eye on them. It is only in the true pacifist route where Undyne starts to fully trust Asriel. In a genocide route, Undyne attacks Asriel.
It is unknown how exactly Undyne and Temmie were involved, but it's known that Undyne and Temmie had some sort of past connection. Undyne's secret room contains a college graduation cap that looks identical to the one Temmie wears in Undertale, hinting that Undyne might have attended colleg.