What is this character name in traditional Japanese?

Hi, I just need your little help of naming this Japanese character I needed in my Literature class.

My character is a traditional character from old Japan. I was inspired by many anime's in making my short story. I was thinking of this character that I wanted to add in my set of characters but still I can't find a fitting name for her. She is not the center of the story but I want her character vital as well to the main hero.

I described her as a princess and a protector as well as she is servant to this some sort of mystical power she held inside her. She is not into the power that lives within her but she can't help it for it is bound to be with her as long as she lives. It's like a curse [and I haven't figured that one out yet].She is unearthly and beyond human-like beauty. She has her hair tied loosely to the side and a silver pin kept her bangs so that her pale face would be seen. Her hair is pure black and her eyes are green. She is slim and tall. She carries with her a beautiful nine-tailed fox of name I haven't yet decided. It is her guardian. She wore traditional Japanese noble clothes. She is the only daughter of a great lord and had not been destined for anyone yet ['coz I haven't thought of that].

When she's away from the castle in the sky where she lives with her father and wore normal clothes, she looks like she's not a human with her beauty beyond compare to those of others. She is kindhearted but then is reserved. She does not talk much to anyone other than her father due to fear that others might use her but somehow that changes when she met the main character. She is usually found in a garden of white roses that is behind the Great Falls that falls from the floating castle.

She is highly skilled of all sorts and has an ability to know if there is an impending danger.

I was trying to find some translation but I can't. I wished her name to have a meaning of "The Castle in the Sky" or something that is very descriptive of who she is not as a person but someone beyond that. And also a quality of wisdom and something that she is unusually linked to the sapphire stone.

I'm hoping for some help, advice, or suggestions so feel free to do so and thank you so much. :)

I have plenty of time to wait for some help and also I just wanted to ask if you could put the meaning of the Japanese name you've thought of. Thank you.