Well, I beat her ass cause I wanted a certain archer man too survive, and more stats over health is always nice, but she seems more canon- 20 chapters seems like alot of decisions too make, will we get too see the others or do we have too play the whole game again?
Not quite.
-There is only 1 or 2 big important choices in each game. In this one was the witch quest and if you summoned the lord of gifts or stand your ground against the duchess.
-I'll ask you at the beginning of each game watch choices did you make in the previous one. Although, be warned, you will lose a lot of information and how things got that way if you decide to just play the 4th game and put the canon choices to see the canon ending.
"Why is this guy using this armor? Who's this new character? Why am I here?!"
^ Things like this XD
My suggestion: If you didn't unlock the canon ending, consider a play-through of the series with the canon choices.