try doing that part again this time dont save it untill you get out of the chamber of fate

GO OUT SIDE THE GIULD AND GO TO THE TEMPLE OF AVO

Do not listen to that guy here is how you get it

1. Make sure to kill your sister

2. DO NOT THROUGH THE SWORD IN THE PORTAL

if you did that i gusse it glitched and you will have to go to your last save

WARNING

KILL THERESA NOT YOUR REAL LIFE SISTER!!!!!!!!!!! but the avo thing find another hint
thing you get the good version of the sword of aeons if you do it right you get "The sword
of tears"