Cults
Throughout history, cults have arisen in service to the strange and malevolent entities of Beyond. While the Cult of the Leviathan is the most notorious - and the one that came closest to success - it is only one among many that have striven to open the flesh of the world to a hungry god. Some of these cults have been eradicated; others continue to operate in the shadows even today. A few even dwell within the confines of the Church itself, though they would take offense at being described as such.
Indeed, some of the Living Gods of Lemuria consider the Church to be the most successful cult of all, for it worships God in Heaven - a strange and powerful entity residing in Beyond. Needless to say, this suggestion is rank heresy among the faithful of the Church and its offshoots, and countless theologians have written exhaustive treatises seeking to draw clear distinctions. None of these arguments, however, have succeeded in convincing the Living Gods of the southern continent.
To Prey on the Mind
The entities that inspire cults do so by seeking out individuals with abnormal psychology - people broken in such a way that they can resonate, however faintly, with the inhuman and alien thoughts of the entity in question. This resonance becomes a wedge, prying open the mind of their prey. Into that breach, the entity inserts intrusive and unsettling thoughts, designed to fracture sanity and graft fragments of its own alien worldview onto the victim's psyche.
At first, a person may seem merely peculiar, but as the entity tightens its hold, the victim's mind unravels. They descend into what we call madness - if madness is the right word for the condition of having an alien psychology steadily invading one's thoughts. Over time, cultists cease to understand the people around them, recognizing only those who share devotion to the same patron and have thus undergone a parallel transformation of mind.
Corruption
If cults relied solely upon those who naturally resonated with the entities of Beyond, they would never be numerous, nor dangerous on a global scale. Yet one of the first tasks of nearly every cult is to create conditions that will break potential recruits in their own particular fashion. The precise methods vary from cult to cult, but the overall process is known as Corruption.
Corruption may employ wholly mundane means, as in the case of the Nameless, or direct psychic assaults, as practiced by the Dream-Eaters. Whatever the method, the experience is harrowing for the victim. In slow corruption, the change may be subtle at first - months or even years may pass before the target realizes anything has altered within them. But eventually, every form of corruption reaches a critical moment: the victim's mind shudders, fractures, and admits a thought that resonates with an entity from Beyond. From this instant, the process is almost impossible to halt.
The outsider presses relentlessly at the breach, intruding with thoughts and alien impressions of increasing intensity. Some cultists describe the sensation as being drowned in another's mind; others as a defilement, their psyche torn apart and remade in a stranger's image. In time, the victim begins to act upon these invasive ideas - and it is at that point they become the foe not only of themselves, but of the entire world.
Cults in the Modern Day
In the aftermath of the Dragon Wars, the world is more vulnerable to cults than ever before. That titanic conflict left wounds upon creation - such as the recurring Eldritch Moon - that weaken the very forces barring the entities of Beyond from entering. Only time will tell whether these wounds are healing or festering. What is certain is that the damage has made contact with patrons easier, and the work of Corruption simpler than ever.
While the cults grow stronger, those who oppose them are diminished. Many of the veteran hunters perished in the wars, taking with them the hard-won knowledge of generations. The groups that remain are filled with the young and untried. They burn with zeal, but lack experience, and most are slain - or worse - within a year of taking up the struggle. Should they fail, the world itself may be lost.
It may be lost already.

I don't know, the Living Gods might have a point... depends if God in Heaven seeps into people's minds or not.
Explore Etrea | WorldEmber 2025
Not everyone's...but it's not out of the question for some of the faithful.