Otaku Elf

Koito Koganei is a teenager who works as an attendant to the Takamimi Shrine. Rumors have it that a deity dwells within the shrine, but the actual resident is an immortal elf who found herself stuck on Earth some four hundred years ago. What's more, the elf is a total shut-in who won't go outside and has developed a taste for video games. <em class=de-emphasized>(from manga)</em>

Synopsis from Anime News Network