Aleister Crowley

Once the greatest magician in modern magic history, more than half of all modern magicians are affected by this man's established theories, and two-fifths of them are direct followers of his ways. Having stretched the boundaries of sorcery farther than the advances made in the last few millenia alone and written an top-class spellbook like 'The Book of the Law', it is no surprise that many mages were outraged when this eccentric genius literally "dumped" all his magic abilities and decided to "ace it" in the field of science, thus establishing the Academy City and becoming its hidden monarch.

When he chose to stop using magic and was running for his life from the entire Magic Cabal, he met the Heaven Canceler, who eventually helped him found Academy City in a far-eastern island of Japan and also provides help in this ex-magician's new goal; to extend his lifespan for as long as possible by having all but his consciousness rely on the power of machines.

In the novels, his appearance is described as someone who 'looks like both a adult yet also a child, like a man yet also a woman, like a saint yet also a criminal'. His personality is of one that doesn't show much overt expressions, but still possess emotions. From the various novels, but especially vol.15, he is shown to be a master strategist, with many plans running in parallel, seemingly abandoning one plan in favour of another if one fails. Though abandoning plans could still be a facade, with it's apparant disbanding another move to execute a parallel plan, or even the original purpose for the plan benefiting from it being disbanded.