In this world, magic is real, and absurdly powerful. Its sole wielders are the mages, control the world with the power coursing through their blood.
They are organized according to Bloodline: Dragon, Devil, Angel, etc.. Because the magic is in their blood, many of them belong to the same family as well, but not all member of a mages family will inherit those power. But once they are confirmed to have magics, they are basically a one-man army; as powerful as a D&D Sorcerer, or a mid-high-tier Marvel mutant, but limited to a theme (Fire, Ice, Blood, etc.). And yes, they do rule (or have a high position) in most of the world.
Among the mages though, there are the very peculiar magicians:
- Instead of recruiting from known magical bloodlines, they go out, find the brightest willing person, then "train" the magic out of them (which is nonsensical, but only the most learned sage know that)
- Their "magic" is not limited to a theme, as long as they can prepare, they can do pretty much whatever they want. Unfortunately, that magic is not very strong (fireballs that don't burn people, work more like flashbangs than fantasy fireballs)
- Their "magic" are not hindered in magic-null zone, or countered by other mages (this will be a plot point later on, when a magician is locked in a magic-null prison, and proceed to hypnotise the guard to let him go free). They are also immune to many problems mages face.
Of course, the truth is that they don't have a drop of supernatural blood in them, the "magic" they practice are just stage tricks (boosted to Now you see me level, using gadget of their own devise), but still mostly work as distraction and confusion rather than direct damage.
On their own, no problem, few can tell the difference. But if any mages decide to challenge them to open combat, they are as good as dead (party trick << bending the rule of the universe). Their only chance is to escape (they can do disappearing tricks mid-fight, also like in Now you see me, but there have to be a realistic way to do it), catch the mage off-guard and go for their weakness, which they have to figure out or research beforehand (each bloodlines is weak to different things, and that is not open knowledge).
The question is: With all those skills and gadget, they can do all sort of things: toy maker, thief, information broker (from their research). Why pretend to be a supernatural being when there is a real chance said supernatural being can come and squash you?
EDIT: About the in-universe magic system:
- A mage get a set of power following a theme from their supernatural ancestor (for example, a Giant mage grow larger, get super strength (even when taking account of size), armored skin, etc.). As they become more powerful, they existing magic increase, and get new power, still from that theme (so when our Giant mage get more magic, they might get a earth-shattering roar, hurricane breath, but he will never get teleport), and become more dependent on magic (if the Giant mage suddenly lose his magic, he get all the problem of the Square-Cube law: bone pain, difficulty breathing, even to out right collapsing on himself. And that was still better than the Specter mage, who wink out of existence without magic holding them together)
- On the other hand, magician is 100 % not magical. Their only advantage over us in this world is that they can do stuffs we consider "action movie stunt". If a person want to become a magician, they have to do it the same way our magician do: find a teacher, devoted time and effort to perfect their craft until they can do stuff David Copperfield would have approved
- The "problems" that mages faces here is basically a mundane way to make them lose their power that is not magic-null zone (which can only be created by high level magic or occur naturally). So for example, still using the Giant mage above, his weakness is, say a shattered ankle. Not exactly easy, but if you can smash a steel-reinforced battering ram through their ankle (remember, at this point the mage is basically a human-shaped mountain), even if the injury and the shock don't kill him, he will still die from the aforementioned Square-Cube law. Obviously this is a closely guarded secret among the families, even the fact that they have the weakness at all. To 90 % of the world, they are demigod. The magicians are regular people with homemade gadget, so magic-null zone is a non-issue, and even if they lose their tricks, they are still more athletic and skilled than most people
- Most members of a magical bloodline are just regular human, who are still nobles, doing most of the management jobs, while the mages are Duke/Duchess, Price/Princess or King/Queen. They cannot blow people up, but their cousin can, and family are more trustworthy than strangers, right?