You'e a wimpy loser with a big heart!Undyne is the Captain of Mt. Ebott's Monster Royal Guard. She is also the girlfriend of Dr. Alphys. She is also a personal trainer to Papyrus. She bears a Green-hued Monster SOUL.
Undyne looks a bit like a humanoid fish-girl with blue skin, accented by red highlights. Without her armour, she has long, red hair.
She is the kind of person who makes bold, rash decisions, but she is nice once you know her. She once thought you can make an enemy in pain if you make them your very best friend. This did not go out as well as she thought.