From Miyabi Fujieda, it's The Miko's Words and the Witch's Incantations AKA The Caged Miko and the Whimsical Witch (Kotonoha no Miko to Kotodama no Mahou) 『ことのはの巫女とことだまの魔女と』. It ran from 2005 to 2006, originally being published in Yuri Shimai before moving to that magazine's successor, Comic Yuri Hime.
Slightly egotistical but certainly not evil Witch Letty (or Reti) is visiting Japan; because in her words, she's an "architecture buff." This hobby has led her into investigating a shrine off in the middle of nowhere; which actually has a magical barrier preventing anyone from entering. Knowing a trick or two, she sneaks inside and encounters....Tsumugi, the local Barrier Maiden Miko who gathers mana from the local mountain god for the government should it ever need it. But it's a task she must do ever alone since childhood.
Her sensibilities irritated that someone would just lock away another human being, Letty impetuously smashes the barrier and declares Tsumugi free. Tsumugi is flabbergasted, as she would have no idea what to do in the outside world that she has never known, and points out that if Letty is so adamant about this, she has to take her with her. And so they run off together into the night on Letty's broomstick.
What follows is Letty and Tsumugi getting to know each other more and more and finding out that they're attracted to each other. But other circumstances conspire that could keep them apart. Tsumugi was kept in the shrine of the Mountain God for more than one reason, and the family in charge of her is out looking for her....
Ultimately a fluffy story with a happy ending.
This manga provides examples of:
- Bargain with Heaven: The Mountain God willingly gives some of her power to Letty so that her presence purifies the air around her, while the god takes Tsumugi's place in the shrine. It's implied that Letty now has to work for the god; but so far all the god seems interested in is hitting on Isuzu.
- "Blind Idiot" Translation: According to chapter 2, Letty comes from Germany. According to the afterword in chapter 6, her full name is actually Gretia Deetolihi, which doesn't sound very German. This is likely the result of a poor translator mangling "Gretia Dietrich", which does sound German, and Reti makes more sense as a diminutive for Gretia, and Word of God also gives her name as Reti rather than Letty.
- Southern German, to be more exact, probably Bavaria or around that corner.
- Captain Ersatz: Muggle versions of Ron Weasley and Harry Potter show up and try to get Tsumugi to join their Cosplay Café.
- Crossover: Letty and Tsumugi in one scene are customers at The Amber Teahouse from Chatting at the Amber Teahouse.
- Did You Just Punch Out Cthulhu?: Letty's intention when she challenges the mountain god to allow Tsumugi to live in the outside world. ...well, her intention, anyways. It gets more complicated.
- God in Human Form: The spell that Letty casts gives this to the Mountain God, who takes the form of Tsumugi.
- New Season, New Name: It was originally called The Caged Miko and the Whimsical Witch until Yuri Shimai became Yuri Hime.
- Red String of Fate: Quite literally. Letty makes a spell to always show her where Tsumugi is; which manifests as an invisible red string that only they can perceive; not realizing the cultural implications.
- Too Good for This Sinful Earth: The outside world is actually poisonous to Tsumugi. Letty and the Mountain God come up with an interesting solution.
- Unsound Effect: The Mountain God offers Isuzu some sweet rice balls with a "Proffer!".
- Where Are They Now: After the last chapter we get a short description of the characters relations after presumably around half a year along with the afterword.