Mettaton is a character in Undertale. He was originally a ghost, but was given a corporeal body by Alphys. When the player investigates the house Mettaton lived in when he was a ghost, they find diary entries written by Mettaton elaborating on his desire for a corporeal body. The house itself is also aesthetic coded as traditionally feminine. After receiving his robot body however, Mettaton refers to himself as exclusively male, and remarks on being excited to show off his new “masculine form”. These character details have led many fans of Undertale to read Mettaton as a transgender character.
LGBTQ References in this game series:
Undertale (2015): Alphys and Undyne; Frisk; Mettaton; Napstablook; Royal Guard
Deltarune (2018): Alphys’ Computer; Bloxer; Kris; Noelle
Citations:
- Minor spoilers: is mettaton trans (n.d.). Retrieved from https://www.reddit.com/r/Undertale/comments/3ofh0r/minor_spoilers_is_mettaton_trans/
- Speight, E. (n.d.). Undertale’s crazy success proves gamers are ready for feminism, queer romance, and progressive values. GameSkinny. Retrieved from http://www.gameskinny.com/2oxox/undertales-crazy-success-proves-gamers-are-ready-for-feminism-queer-romance-and-progressive-values
LGBTQ Video Game Archive 
