Hades

Hades, known as Purehito back then, became the second Master of Fairy Tail after Mavis Vermilion. Some time later, in the Year X736, Purehito appointed Makarov (40 years old at that time) as the third Master and his successor, much to the man's dismay. Ignoring Makarov's claims that he wasn't fit for it, he praised Makarov's love for his allies and his capability to believe, claiming that he would have made Fairy Tail into a good Guild. He then left on a journey.

On such journey, he traced the roots of Magic back to Zeref, where he saw what can be called "the Essence of Magic". It is presumably around this point that he reformed his ways and became a Dark Mage, and then founded Grimoire Heart, raised and trained the Seven Kin of Purgatory, teaching them different forms ofLost Magic, in order to acquire this "Essence of Magic". It's known that he personally recruited Ultear Milkovich, nearing her while she was a child and promising her that, in the Ultimate World of Magic, the Arc of Time Magic which he would have taught her would have allowed her to travel through time and change the sad events of her childhood into happy ones.