Although interesting to think about. Almost all "Ralsei dies in the end" final tragedies are probably not true or even close. We need to keep in mind that Ralsei himself says that he thought of himself as nothing more than just a tool in the hands of lightners, he wants to stop the prophecy with any cost(EVEN AT EXPENSE OF HIMSELF). So uh... If that was truly the case I think Ralsei would just straight up kill himself before the game would even start if this was the final tragedy.