Debeth is typically depicted as a stern, but calm older man, with a disquieting direct look that hints at a deep knowledge of the on-looker.
Priests of Debeth are conservative men (and sometimes women) that make ideal archivists and administrative workers. A lord having one in his services will always have crucial information at hand, and the more economically-minded rulers find them beyond praise.
Rarely preaching publicly, they instead focus on smaller groups and individuals, spreading their views in this way.
Privately, the priests are not a very creative bunch, and tend to admire scientists (don’t forget the definition depends on societal context), discoverers and others, that test the Unknown and defeat it, bringing precious knowledge untouched by human mind before. Those that rediscovered what was lost are treated with similar respect.
For powers, see the Path of Days Gone By, a renegade group that have left the Truth.
It has to be admitted the religion does not have masses of worshippers, nor are they particularly devoted. Sympathy comes from sages and scientists, amateurs as professionals, mostly from those that appreciate their supporting role in gathering and cultivating knowledge. Even where is a high literacy will there be not much interest. To the public eye are they harmless and a bit strange, mostly ignored.
Treating knowledge so highly, the order is a bit touchy on the subject of truth. Being no fools, they recognize the inherent danger of naked truth, particularly when it is confronted with people that have no interest in it. At times, they are very tempted to distort the facts, or at least present them so as to not shock entirely the audience. They are well aware, that some truths are less significant than others, but the thought of something true being lost forever produces irrational fears in them - if smaller Truths can be just ‘wished away’ and forgotten, so can bigger Truths, anything can! Thinking of this, they would make warding gestures against Evil, and mumble of unspecified forces older than our world, who wish to consume our reality and dissolve it into nothingness. But they will rather change the topic; most of the time they are very rational guys.
Darkness follows the Light
Some seek to worship this deity for their own ends, and it is not only search of knowledge. Being wronged, but unable to pay back, being conspired against by unknown enemies, or sentenced for crimes they did not commit, they wish to expose everything in the unmerciful light of Truth, be the cost ever so high. Those that succeed (and survive) are rarely content though - the exposure to Truth also exposes their own life to them, with all the mistakes we apologize to ourselves as faults of others, and all those rose-coloured illusions clouding our sight vanish… leaving most broken or ready for a suicide.
Some priests liken the Truth to the Sun - it is life-giving and all-important, but too much of it may destroy you… there are also a few sick individuals, who look for such moments and such Truths to make public. Beware them.
History books mention the king Hieronym the Second, who hanged a priest of Debeth for some imagined insult. The priest’s name, that should be forgotten for all eternity, was Nemert; but the king is also remembered until today. For in a single week following the execution, all of his secrets were revealed by one accident or another - the romances with servants (of both sexes), court intrigues against his nobles, as the plans of war to the neighboring kingdoms. His rule toppled in a short order, and the king has fled in the clothes of a beggar, to meet an unknown but surely low fate.
The order has stressed relations with the School of the Path, a group that has split off a few centuries ago, taking the secrets of many mental techniques, abandoning the search for knowledge as any pretense of being religious; instead they serve the wealthy and powerful. (Note that a priest of Debeth will have the powers of that School and more, their rivals manage to be more popular anyway. If members of these two groups meet, trouble is never far.)
- the PCs could need some information for which a priest of Debeth is an excellent source - but also one that is known to be not bribed easily. Needed is a tricky way of getting the info out of him.
- someone has made something not quite nice, like committing a lesser evil to prevent a greater evil - perhaps even the PCs? Somebody is harmed by it, and swears revenge. Will they be able to stop a lowly villager, with the drive and unexpected supernatural support? Or will everything be exposed?
- intending to destroy evidence of something forever (how to summon this demon, a new potent magic powered on sacrificed human souls, etc.), there is suddenly a strong opposition from one priest - as you cannot foresee all possible futures, and what is dangerous today, may be vitally important later. Solve that.