Clare started off as a man, actually. He was neurotic, slightly obsessive, and flamboyant. He thought he had produced the perfect horse (taking 200 shadow-years to do so), and had spent a lot of time studying the fundamental aspects of the Universe - he loved the discipline and feeling of walking the pattern (physically and of the mind), and applied himself to mastering trump. By this point, I was thinking of pattern and trump artistry.
Further reflection made him the sort who had walked the pattern multiple times - twice in Rebma and Tir-na Nog'th, was at least part-time resident in Rebma, and having only recently finished creating his horse was looking for his next great challenge. At about this time, he became she. She also needed advanced pattern, and I worked out the mechanics of the horse she had made [engine speed, speaks in tongues, invulnerable to conventional weapons (transferred)]
Tir-na Nog'th is a place of prophetic visions; the first time she walked the Pattern there, she saw a vision of a great black stallion, which is how her labours began. She wishes to walk the Amber Pattern soon, to see where her next labour lies. Her flamboyant side enjoys a good Hell-ride in the morning...
At this point, she was nearly complete. Physical details were hammered out, she was named (as was the horse, Nathaniel), her trump deck was sorted out (standard, plus PCs she'd met before, Queen Moire), as was her tutor (Llewella). Her parents are unknown, something she'd like to rectify. All that was needed was the first diary entry, and she was ready to play. The attribute auction was not as good as was hoped (top Psyche would have been good), but acceptable, and she bought up a little afterwards. The finished character: