She was actually a puppet made by ganon and then ganon will tell u that he used the puppet to make fall to his trap and then the puppet becomes phantom ganon and it will start a boss battle
Also you are wearing the mask of awaking with the campions leathers and soldiers greaves with a mighty lynel bow and hylian shield fused with a mighty banana and I think a pristine nights broadsword with a whole bird correct me if I’m wrong
It’s a very late game cutscene so it’s very hard to tell any spoiler free info but how many sages have you been to then I might be able to tell you more