////// SPOILER FROM HERE !!!!! ////
Regarding the possibility of the character that has survived until this time and through time without the circle is closed, I think it would be better for those who are still asking questions they reread the passage where we discover who it is. Indeed, the character - and prophecy - make clear that this character is immortal TO BIRTH Ruby. Then, to be again, he will have to hang the famous powder (we will call "philosopher's stone"?) In addition to the disappearance of Ruby. This is explained clearly enough but I understand that one can miss accidentally.
