Curate, connect, and discover
I was watching some old fairy tail episodes and I came up with a theory about natsu if he does kill Zeref all the guild needs to do is get him to TENROU ISLAND and because The Great Tenrou Tree will protect anyone baring the fairy tail guild mark from dying as long as they are on the island. So my theory is that Natsus and Zerefs final showdown will be on TENROU ISLAND so Natsu won’t die