A. Name: Ilyn.
B. Zodiac Sign and/or Hogwarts House: Elder (http://www.whats-your-sign.com/celtic-tree-astrology.html).
C. Circumstances of Conception: A canon-swapping glitch swept through Taxon, and some things stay the same; Petrana never, ever goes for the hero of the story. Petra Saxon wore smart heels and tailored red suits, and would have been a lot more prepared for an unplanned pregnancy than the Countess was when the dust settled and she'd burned the suit.
D. PB/Appearance: Morgane Dubled.
E. Three Random Facts:

• Petra managed to keep a tight lid on the truth of her third daughter's paternity; the timing was a little murky, with Davidias's arrival shortly after conception still within the right timeline for Ilyn to be his.
• Unfortunately, not even Petra's witchcraft could account for the early development of minor psychic ability.
• Davidias and Petra made their peace with it - hardly her fault, etc, etc, had been raising Ilyn as his, Petra hadn't even been sure whose Ilyn was - and proceeded to spend several years stealing her back every time the Master decided to kidnap her for fun and games.