Oh, no, I get that current Roselia is now the Holy Beast of Fire, I'm just wondering what exactly happened to the original. Roselia admits she doesn't have all the original's memories and it often shows when she is asked about things "before her time (when the Dark Dragon was defeated 800 years ago)" The original told the then-familiar Roselia to head to the Luna Sanctuary if something happened to her and obviously something did but I'm wondering what exactly happened. The number of things we know that can kill a Holy Beast are extremely limited. Even the curse didn't kill the Holy Beast of Earth and if there was another Originator Zero just lying around back then what happened to it that the Gnomes didn't just go get that instead of enacting a 800 year plan to get a new one?
Current Roselia = original Holy Beast of Fire. Original Roselia was not Holy Beast of Fire. I don't think she has full memories of her Holy Beast of Fire days - might not have been totally sentient then. ---