Yotsuyu seems to have been stricken with amnesia (g-gasp!). That's how it seems to me. This is an interesting thing to do, as it essentially gives her tabula rasa - a blank slate, colored only by her inborn nature. "Tsuyu" is, well... Yotsuyu minus the painful past that shaped her, meaning who and what Tsuyu becomes is entirely up to her experiences and how others treat her. It's a very interesting predicament, because it raises many questions... chiefly "Should Tsuyu, who does not remember Yotsuyu's crimes, be held to account for them?"

... I don't think so. The Domans, on the other hand... well, mob mentality is a real pain in the ass, and even though Yotsuyu will have figuratively died they'll still want vengeance. We also know the Alliance... doesn't seem to share this philosophy, as if my memory serves me correctly they executed the creator of the Black Rose poison despite him being amnesiac or driven insane by guilt (one or the other).

I'm interested to see how this develops.

The real question I have is, why didn't Gosetsu just go to the Sekiseigumi or EATC office for help? He befriended the former and the latter should know who he is...