Undertale s/i!
This is Kei Enmastal :)
They were a classic gifted kid- took college classes in highschool and just fell short of graduating with an associates degree. They slowly lost all motivation for school, grades and accolades just felt so hollow. Tired of the mundane life, they decide to hike up Mt. Ebott with no intention of returning.
Predictably, they fall into the Underground and briefly comes face to face with Flowey, who heckles them. Instead of being intimidated, Kei is just annoyed. Toriel shoos Flowey away and takes Kei through the ruins, showing them all of the puzzles. For the first time in years, Kei finds themself getting excited to explore things, and is eager to explore the rest of the Underground despite Toriel's concerns. They have the idea to make a mask to blend in with the monsters, and makes it look like a flower because of their run in with Flowey.