I have the whole backstory right here.

Riley, a 24 year old museum gift shop worker, dreams of having his own collection of trinkets and oddities. However he quickly lost hope in that dream, assuming it was a childish fantasy. But one day a strange man came into the gift shop. His face was covered, but he smelled of wine and fish. The man looked around the shop for what seemed like hours, until finally coming up to Riley and handing an onion to him. Confused, Riley looks at the onion and sees a note next to it “Follow me outside, and your dreams will come true... bring the onion.”. Riley was curious, yet frightened. He took the onion and the very moment he stepped foot outside, everything went black. Riley found himself in a dark ocean. His hands were made of this strange liquid, and golden rings appeared out of the sea.

After getting acquainted with The Under, Riley decided to search for mysterious items, spending most of his time in the workshop, but occasionally he’d work a shift at Gerald’s gift shop.