Kamejiro

In the Land of Wind, in the imperial capital of Ventfleur, Princess Natalia is enthroned after the loss of her family. The princess, idolized by her people as a "child of the spirits", only has her family's royal blade to assuage her grief. And in her mourning, she's approached by the cheery and elusive Sister Sara... who declares to stay at the princess' side as her duty, as a sister of the cloth. Or is she after something more...? So begins the fantasy yuri adventure of a lonesome princess and meddlesome nun! Note: Was commercially serialized up until chapter 17 when it was cancelled. The author decided to continue the manga via self-publishing. Here is the amazon link

The adventures of a lonesome princess and meddlesome nun. (It's recommended you read the serialized manga first, in the related tab.) Volume 1: The original self-published story. Volume 2: Pre-serialization extras. Volume 3: Post-serialization extras. (Extras take place outside the story. The canon's best described as 'under construction', continuity's nonexistent, and the chapter numbers are simply the order I translate them in, not the order they were drawn. If they have serious plot spoilers I'll mark them as such.)