Zeref

The legendary dark mage Zeref is a human wizard known to history as the strongest and most evil mage to ever walk the earth. He lived over 400 years ago, but even to the present day his legacy continues in the form of other dark wizards and dark guilds who worship Zeref's power. In fact most dark guilds were founded and operate under the pretense of reviving Zeref, and helping him to conquer the world. Not only was he an incredibly strong mage, but he was also regarded as a genius, and he used his immense intellect to try to research and discover new magic, regardless of his status as the most powerful human alive. He is also responsible for the creation of tens of thousands of demons by means of his living magic, and these demons continue to roam the earth, leaving trails of destruction behind them. Aside from living magic, Zeref was also a skilled user of death magic.