WARNING FOR DELTARUNE CHAPTER 5 + WEIRD ROUTE SPOILERS
For the longest time I've struggled to wonder why Dess, as a monster living in a town populated mostly by other monsters, would want to be a human. However, Deltarun Chapter 5 has made me realize why that may be.
A lot of people have begun to speculate that by going into the lake, Kris and Noelle have broken (through) some kind of barrier. Many have compared this to a quote from Alphys where she basically tells the player that a human soul isn't enough to cross the barrier alone: it takes both a human and a monster SOUL. If Dess was a monster, she'd want to be a human so she could leave the town, or she'd want to take Kris with her because she'd only be able to leave if Kris came with her. She's a monster, and they're the only human in town. The combined power of their SOULs would be enough to break out of the confines of the game.
Honestly, Dess could have also wanted to seal dark fountains, too, and she could have only done that with a human SOUL. The only human in down would have been Kris.
Now that I think about it more, if Dess was a human who was insecure about not being a deer monster like the rest of her family, I doubt she'd have so many red heart-shaped objects in her room. They resemble human souls. I feel like they would just make her feel really insecure about being a human.
I still believe Dess is a human though, I feel like I've supported it too strongly to say I don't now. Human Dess dies with me.
Can't help but go all in. Heterochromic snake eyes can't win