Myla is an NPC in Hollow Knight. She is a happy little miner mining for treasure near the entrance to Crystal Peak.

Lore While searching for something valuable hidden deeper within the crystals, she enjoys singing and wants to come up with some songs of her own. Myla hears the crystals singing and whispering, hoping to find them and hear what they are saying.

Eventually, Myla becomes Infected, her cheerful song changing. The voice of the Radiance appears in her mind, commanding her to kill the Knight. In the end, the Infection overtakes her, making her become hostile. However, the song she always sang remains in her thoughts.

More facts here: https://hollowknight.fandom.com/wiki/Myla