I doubt Levi will end up dying,since there was a Q&A back in a monthly manga mag. that asked who was the child that was made between the Ackerman and Riess families as a truce.The answer was supposedly Levi.People also figured it out by the hints given during the chapters when Eren was captured,and about to be titan food to Historia.Rod made a certain remark about Levi to never become a titan due to some secret.