Oh this is gonna be great if it will happen! I think that they did the same as for Hilde, they will introduce her as young and then she will be as we know her an 24 years old adult Setsuka and her story will take place in 1587-1590 I assume! I'm dying to watch how Kokonoe adopted her, raised her and how he teached his style! And also why Mitsurugi killed him!I'm curious if she meets someone which we know. I hope for Li Long. I do not make part of his fanclub, but I think he deserves at least a good cameo, I actually expect see him in Maxi story as Zhang Wu.
and how young she will be in this game?? I mean, she already knows Shugen Kokonoe. They could introduce her as young Neve, a girl who live alone and in the end she meets Shugen Kokonoe and she becomes "Setsuka". Judging by Hilde story I don't think we see all her revenge plot, I think they will work on this in next sequels.