User blog comment:Observer Supreme/Who built the Tower of Heaven?/@comment-26523876-20160125001721/@comment-25400375-20160127032336

No, I meant the Tower of Heaven. I don't have the details, but it appears that, once upon a time, as Erza was revolting against the slavering cultists, Jellal got separated and then brainwashed by someone he thought Zeref which turned out to be Ultear.