So, um, inspired by earlier but hopefully avoiding the 'nothin' but fighting' and inconsistent characterisation things...
Name: Houraisan Kaguya
Universe: Touhou Project
Personality: Polite and with an old-fashioned manner of speech, Kaguya tends to be rather... naive, as well as somewhat silly. All of the rabbits of Eientei are given the same name--and briefly looking up acid rain made her want to keep them all in side one night in case it burned off their hair. She's also been trapped by bamboo growing surprisingly quickly. Whilst Mokou tends to take their feud deadly seriously, to Kaguya it's more like a game, and she doesn't even bear Mokou all that much enmity--most likely because she's the closest thing to a friend rather than a retainer, though Eirin's been warming up over time.
She likes showing off her treasures.
Powers/Skills: Exactly like Mokou, Kaguya cannot truly be killed, and she'll simply shrug off the damage--though aside from that, her personal abilities (except for flight) see very little use. She has 'control of eternity and the instantaneous'--with the practical effect being that she can stop the passage of time from changing an area, or an item, or she can undo effects that similarly mess with the flow of time--in this way, even though centuries passed in Eientei, no food would rot and nobody that lived there would age. Her only other noteworthy personal ability is that she's far, far stronger than she looks: Kaguya can lift up an entire temple ceiling with her bare hands. The only question is
how.
The most likely answer is that, despite being a princess, she knows magic of some description... especially because the Lunarians are supposed to have
invented magic in the first place. Still, with Kaguya being Kaguya, this is... less than threatening. 'Anaemic magical bullets' are about all you need to worry about.
It could also be considered a skill of sorts that she's so beautiful her time in public lead to every noble wanting to marry her, despite the fact that her adoptive parents were common peasantry.
Brief Bio: Born as royalty upon the moon, Kaguya was exiled for getting Eirin to make the Hourai Elixir. Exile, rather than execution, because it was rather impossible to kill someone who is immortal. She was found by a bamboo cutter and raised, again, until such point that every high-born noble came to try and win her hand. Rather than simply reject them, she set impossible tasks--impossible, because the items were already in her possession.
When Lunar emissaries were sent to tell Kaguya she could come home, she decided that it was better, in fact, to stay on Earth, and since Eirin was amongst them they went off to live in a bamboo forest, with rabbits. Kaguya has basically stayed in the house and its immediate environment since then, having left the forest basically once.
It's doubtful whether she's actually left home unaccompanied at any point in her life. She's rather sheltered.
Equipment: As a collector of strange and unique artefacts, Kaguya tends to have a lot of odd things lying around--but not, in this case, on her person. She still nevertheless has her five Impossible Requests: the swallow cowrie's shell, the fire rat's robe, the buddha's bowl, the Jewelled Branch of Hourai (which is only impossible because the tree grows on the moon), and the dragon's jewel. About the only useful abilities these have except as a focus for pretty danmaku patterns is that the robe is fireproof.
She also has an umbrella with her.
Other: Not, exactly, the biggest threat. Though she can probably kill a person with her bare hands.