[list][*][u][b]Name:[/b][/u] Houraisan Kaguya
[*][u][b]Gender:[/b][/u] Female
[*][u][b]Appearance:[/b][/u] [img]http://safebooru.org//images/743/04e182cccfd58de362a3458faa68d531669d5d1c.png?749028[/img]
[*][u][b]Personality:[/b][/u] Kaguya is both a princess--raised to be courteous and personable--and someone woefully bereft of common sense. This probably explains setting people literally impossible tasks to be her suitor rather than declining outright and how she decided consuming the elixir in the first place was a good idea or even remotely necessary. It also clearly outlines why, despite being regal when the situation calls for it, her general attitude to life is to pursue random whims such as having a hotspring in Eientei or to fall asleep somewhere that bamboo can trap her. Given how many rabbits live in the place, she obviously has a fondness for them and yet refers to every single one as Inaba, even the newest arrival from the moon, when that would work as an accurate name for exactly one of them.
She does seem to be able to be inventively malicious towards Mokou, such as sending people to be assassins, but on the whole she doesn't take the whole thing anywhere near as seriously.
[*][u][b]Species:[/b][/u] Lunarian
[*][u][b]Abilities:[/b][/u] Kaguya's (notable) power is Manipulation of Eternity and the Instantaneous. In practical terms, it means that she can break spells affecting how time flows once she's aware of them. Less practically, it's a really good way to keep a mansion in perfect condition for centuries at the cost of nothing there ever changing at all, which is more than a bit boring. This ability is one of the key ingredients to creating the Hourai Elixir.
Naturally, as one of the people instrumental in its creation, Kaguya has consumed the elixir and benefits from all its attendant effects, such as the inability to die, fall ill, or not needing to eat or drink. Of course, injuries accumulate and take time to heal, but she's at least well-fed and quite durable anyway, so it's not an enormous difficulty. Being a Lunarian helps somewhat, as she was already (practically) unageing before consuming the elixir.
[*][u][b]Skills:[/b][/u] Well... she's really pretty? 
[*][u][b]Brief Backstory:[/b][/u] Despite being a princess, she had Eirin make thethe Hourai Elixir for no particularly good reason, and got thrown off the moon as a result. Then the whole Tale of the Bamboo Cutter happened and she chose not to leave. For ages, she's been hanging around in Gensokyo, staying at home with her rabbits. For a few centuries, she's been fighting Mokou and has gotten somewhat bored of staying always at home.[/list]