7thGARDEN

is a Japanese manga series written and illustrated by Mitsu Izumi.

Plot
As a gardener served in a rural manor, Avin wished nothing more than peaceful days along with his lord's daughter, Marie. One day, he accidentally woke up a demon sleeping in a nearby mountain. What she wished was to have him as a servant before felling the heaven and turn this world into her garden. Avin of course declined the offer. However, not long after that, the town Avin staying was suddenly raided by Knights Templar who supposed to protect the country. Avin was then presented with choices: Will he perish along with the garden and his dear ones, or become demon's servant and have this world perish instead.

Other Sources

 * MyAnimeList