Maribel Hearn is a university student in the near future of the outside world in Kyoto, who forms the "Secret Sealing Club" with Renko Usami. She has no relation to Gensoukyou, but has often visited it in her dreams.

She majors in relativistive psychology and sometimes has difficulty telling the difference between dream and reality (at least, in regards to Gensoukyou). She believes subjectivity to be more true than objectivity. Her clan has had the ability to see boundaries since "ancient times" and seeks to dive into another world, despite such a thing being forbidden.

Together with her friend, Renko Usami, she has an interest in what would be considered the paranormal. Their club, consisting of only the two of them, describes itself as a club for necromancers. However, they don't do many of the things necromancers would normally be associated with. Instead, they investigate the possibility of other worlds and such. Specifically, they're interested in Gensoukyou, the Netherworld, and the Moon, and seem to be among the few, or even the only humans from the outside world who know of Gensoukyou's existence.

(Source: Touhou Wiki)