Thank you all for having me. All I have so far is a name, a concept, and a scrap of backstory. I'll have to look to see which House fits her best.
Morticia of (House tbd) is, basically, obsessed with death. Ever since she saw her family killed before her eyes, and knowing that it could have been her if that magus hadn't showed up when he (or she, haven't decided yet) did, she would have joined them stood in queue at the Pearly Gates.
I picture her as a necromancer. Early on, she would learn the healing spells, to know exactly how the body works. She would also be strong in Mentem, for the conjuration of spirits. Her eventual, long-term goal, possibly a life-long quest, is to conquer death. Not necessarily to keep them from dying, but to ensure that they don't have to stay dead. By far her strongest Art would be Corpus, though.
(eta) By the way, I'm off Wednesday, and we're expecting scattered thunderstorms, so I'll probably be staying in, which would (theoretically) give me time to work on Morticia.