Very cool design, but I have some serious worries about her power level. I've found Spawn very nearly broken at times, mostly based on his 9 Life and Regeneration. Especially because he can wound without attacking, which Sersi can do, at almost the same ease (8+ instead of 7+). Sersei also lacks the take-wounds-from-attacking part that Spawn's healing has. Her cost is much higher, which helps, but I would feel safer at 6-7 Life.
Then there's Matter Manipulation. Very cool, but also very good. She has to give up her full turn which helps keep it in check some, but it's still a wound and a half on average. 4-5 per round, with the potential for 9 wounds in a round. It also makes her by far the best healer in the game. Pair her with Jocasta or Aaron Cash and they can keep anyone alive indefinitely. Or you could just use Jocasta/Cash to keep Sersi alive while she deals out crazy damage. Couple suggestions for tweaking the power:
- change it from skulls to shields
- make her choose between healing or dealing damage on a turn (no mix-and-match)
- similar to the one above, but change healing to happen on shields or blanks. Or even damage on shields and healing on blanks