So what was the deal then with the woman that brought him back to life?

Im going to be honest and say that i didnt really enjoy this movie too much. I thought it was fairly slow, but the main reason i didnt like it is due to the fact that things happend and people did things, with no explanation to them at all.

Mainly....So why was that ittalian prostitute able to bring Grégoire de Fronsac back to life from the dead?, how did she have the ability to do that?, what was she really?, i dont remember this being explained in the movie at all. Its like....she just did it....the end.

We first see her in the movie inside a brothel posing as some flamboyant mysterious prostitute, and she has actual sex like a prostitute. Later on in the movie she gives Grégoire de Fronsac some food while he was in prison and poisons him to death with it. Then she brings him back to life from the dead. Why??, how???, none of this was explained. I cant stand movies that do this, make things happen just because, with no background reason to it. This is why i thought the 3rd pirates of the carribean movie was a load of garbage (this woman turns into a giant and then attacks the very people she was allies with.....well because she can and does).

Towards the end she tells Grégoire de Fronsac "maybe i should hand you over to the pope". So if she was working for the vatican, that totally makes her being this prostitute totally come into conflict with all this.