18/2/2022 · Like Papyrus, Undyne also has an UnderNet account, which is named StrongFish91. If we’re to follow ...
Undyne ( /ˈʌnˌdaɪn/ UN-dyne ),  known as StrongFish91 on the UnderNet, is a fish-like monster that leads the Royal Guard. Clad in her full suit of armor, she pursues the protagonist through the entirety of Waterfall and is frequently evaded or inadvertently thwarted by Monster Kid . Contents 1 Profile 1.1 Appearance 1.1.1 Normal
I'd say Sans is in his late twenties, since I can't imagine him to be very old. Papyrus is about 17 to 20. He has a job, he takes care of his brother, but he's also a bit of a child. Undyne I'd put as a few years older than Sans. Since she's a captain, I imagine she's had time to work on that. She's probably 35 at most. Alphys is about 28 or something.
That means Toriel, as well as Asgore are well over 1000 years old. Undyne: 25-35. Undyne is the captain of the royal guard which places a high responsibility on her shoulder which would only be given to somebody of around this age and must've taken at least half a decade to meet the qualifications.
Undyne is about 20-24. All characters with JOBS are over 18, please keep that in mind, (also please don't ship characters that have awfully large age gaps.) A message from your friend, MuradisDaBeast (also, PLEASE TRY TO FIX THE UNDERTALE FANDOM BECAUSE THERE IS ALOT OF RULE 34 TRASH; DONT SEARCH UP WHATEVER THAT IS-)