First though, a word about magic in general. The divide in this world is not so much cleric vs. magic-user (though, a similar divide does exist, in a fashion) but thaumaturgy vs. mysticism. Thaumaturgy is the applied science of magic, the exploitation of forces and principles as real as physics or chemistry are in our world. There are many competing models as to the "hows" and "whys" of magic, but whatever their differences, they all typically involve spells/formulae, magical aides/tools, and experimentation. Mysticism, on the other hand, is less rational and more intuitive. It relies on idiosyncratic (or even lack of) explanations. It's tools are things like meditation, physical conditioning, and/or use of drugs to create altered states of consciousness to achieve sudden insight.
With that in mind, here are two men of magic from the streets of the City:
Jim Nightshade
Nightshade's got a one-room office with "Nightshade Investigations" stencilled on the door. He solves problems. Particular sorts of problems. Kinds the cops won't.
He used to be a cop himself, but that was before the War. Then he had uniform and a badge. Now he's got trouble sleeping nights--and magic. He used to think he was just lucky, but luck had nothing to do with it. The ageless man that visited him in that hospital overseas clued him in, and gave him a book--a grimoire--the first of many.
The upside of insomnia is a guy's got a lot of time to read.
The so-called "Gentleman Mentalist" is a highly-paid performer and celebrity exposer of criminal mages. He dates starlets and popular songbirds, and appears in advertisements for pomade, cigarettes ("Djinn Cigarettes--your wish for flavor is granted!") and men's shirts.
This public persona doesn't tell the whole story. His real name is Alisander Welleran and, despite his image, he's taken an oath before the Nine Unknown Sages of Agarthala to defend this plane against the forces of evil. Time after time, he's put the mystic powers he mastered in Agharthala to this purpose--and if he can increase his celebrity thereby, so much the better. He's thwarted Anarchists trying to poison the City's water supply with flesh-warping alchemicals, and bested a murderous shade striving to re-enact its pre-death killing spree, among other exploits. And he's always looked good doing it.