Fuyumi is a Japanese high school girl who somehow ended up lost in the Demon World—a place she definitely wasn't supposed to be. Things went downhill fast when a carnivorous plant ate her, turning her into a ghost. The small triangle headband she wears is basically her mark as a ghost, a permanent reminder of what happened.
Despite being dead, Fuyumi's still got her humanity (literally and figuratively), which is actually a huge part of why Staz became so obsessed with her in the first place. He's constantly pestering her about anime and manga from the human world, genuinely curious about where she's from. Fuyumi's main goal is to get resurrected and return to her human life, and Staz is pretty determined to help her make that happen—though his motivations are. complicated.
Content compiled by AnimeList.moe from publicly available sources.