Conundrumism

Truth is an illusion, knowledge can be foolishness, fiction can be truth. This philosophical school is dedicated to understanding perception and delusion, and how delusion builds the world as much as fact. For thousands of years they have studied the effects of illusions, the malleability of memory, the way conviction and belief can change the world as much as facts, or that facts and truth are hollow.
The trickery domain is their focus and they are masters of illusion, and deeply in tune with mortal perception. Left to their own devices they study illusions, practical optical tricks, but also how to people convince themselves of their delusions. They take in the insane and disturbed and study them, and when they can help them cure themselves. They also take in the criminal, extremists, cultists, and other who have no ailment but are living in a different reality. This is not always voluntary either.
Within many cities there is a sprawling complex hidden in plain sight that is the Den of Illusions, a fun house built to disorient, confuse and challenge the individuals who enter it. deep within is the sanctum where the Conundrum is in study. Here they run psychological experiments, conduct therapy, and observe behaviors. They also experiment with numeria, magic and medicines to see how they affect perception, cognition and consciousness.
Sometimes they have outreach in the form of rehabilitation for the mentally ill, and may even work with the legal machinery of the city to take in some criminals rather than send them to jail. Reformed some of these in turn become philosophers of the Conundrum.
Adventurers may be given nonsensical quests as part of an observation, and when they understand how well they perceive reality they may give them real quests to bring back items or people they are interested in studying.

Type

Religious, Deanery

Philosophical Clerics: These characters could have any background, and have spent time working through their illusions, perceptions and delusions in the Den and are now going out into the world to help others see through their delusions with the power trickery. Conundrum clerics are not fighters, so they tend to use light armor and simple weapons when out in the world for protection, if they choose to use those at all. they also tend to like disguises, camouflage and stealth as their armor.
Philosophical monks: the Unseen Fist is the official monastic order associated with the den of illusions. their invisible members train in a secret hall, they are never seen and their attacks are imperceptible. (it is also possible no monastic order actually exists, or that they are trying to make one appear our of thin air based on the popular perception it exists)
Philosophical Paladins: Paladins of this order are rare, and probably started as something else became disillusioned with their previous path and fell into mental illness and were repurposed over many years in the den of illusions.