User blog comment:Miskos3/Episode 275: Fairy Tail Zerø: An Eternal Adventure, Review/@comment-24499036-20160312115441/@comment-7418318-20160313123618

Calling a prequel Zero is actually quite common in anime and manga.

Macross and Fate/Stay did it, to name just two.

But naming the manga/arc and Zera in conjunction to make this play with the name was a nice move.