User blog comment:Miskos3/Fairy Tail 522 & 523: Gray's Trump Card & Is Destiny Burning, Review/@comment-25111584-20170218071635/@comment-7418318-20170220071034

The difference between Zeref and the cliché villains is that Zeref literally can't die. Even if he loses, he'll still survive and he has literally all the time in the world to do it again, since he is immortal. And so are Mavis, who's power he tries to get and Acnologia who he's trying to kill as a side dish to whatever his true objective is.

But even if he were to die, that would be great for him since he wants to die. Actually that would be even better for him than winning.

Then there's also a very real possibility that for Zeref this entire conflict is just a game. After all he views all the people in Alvarez as merely his game pieces, which was how he was able to avoid shooting off death-waves left and right.