User blog comment:BlackWizardZeref/Fairy Tail: Chapter 436 Memoirs Review with a brief mentioning of Chapter 435 Victory Shout!/@comment-77.194.131.45-20150519091211/@comment-24039250-20150519183840

Yep. I'll bet they never actually met END and were only going on the info that Zeref told them about END.

Zeref: Listen guys this Book contains END. He is the strongest of my creations, and is a Fire attribute Demon.

Mard Geer: "What does he look like?.....wait Zeref why are you crying?"

Zeref: "...sniff Shut up."

Mard Geer: "Never mind, I'm sure we will know when we see him."