Much is said about occultists choosing the path of making their mind a gateway to the paranormal, in an attempt to use it against itself, but every now and then, a combatant is brave or insane enough to do the same with their body.
Paranormal Order RPG: Surviving the Horror
Monstrous are the combatants, whether agents of the Order or not, who choose to open their bodies to the Other Side. They purposefully disfigure and alter their physiques so that the Entities can invade them more easily and intensely. However, the methods for this are usually brutal.
Despite warnings and previous disastrous results, the temptation to use the paranormal against itself is very strong. Some agents, driven by pride, naivety, or desperation, end up following this path, believing that with them "it will be different", and that they will be the ones to stare down the Entities and use their power for good.
They are always wrong.
Being a Monstrous represents a quest for power that inevitably turns against the individual, exacting the highest price: the gradual loss of humanity. Monstrous who reach the highest levels of paranormal exposure inevitably lose control; not only of their actions but also of themselves.
If the Monstrous is a member of the Ordo Realitas, at a certain point, their actions are no longer accepted by the Order, which will ban and potentially hunt down the former agent. Someone in this situation can still assist their former colleagues but loses all support from the Order.
In addition to all this, Monstrous is also one of the Trails in the official supplement Surviving the Horror, from the Paranormal Order RPG Playbook. Below are the general, physical, and mental paranormal alterations that a Monstrous undergoes. If you want access to the alterations of each Element and the mechanical details, consider purchasing the supplement.
Alterations[]
10% EXP[]

When reaching 10% Exposure Level, a Monstrous begins to feel the effects of a curse coursing through their veins, slowly transforming them into a monster. This transformation is marked by the necessity to incorporate a paranormal element into their daily life. They must choose between Blood, Death, Knowledge, or Energy. Once per day, they must perform a ritualistic step involving this element (for example, drinking human blood for Blood, inhaling ashes of the dead for Death, tattooing fear-inducing words for Knowledge, or receiving electrical shocks for Energy).
This ritual is crucial for the Monstrous to maintain the effects of their curse. Failure to perform the ritual results in insatiable hunger and thirst consuming them until the end of the day.
Additionally, the Monstruous gains resistance to damage from the chosen Element, but experiences a decline in performance in certain activities.
25% EXP[]

When reaching 25% Exposure Level, a Monstruous feels chills down their spine before crucial moments, experiences increasingly frequent déjà vus, and their nightmares become more vivid and intense.
Additionally, the Monstruous develops a specific (and variable) physical or mental change that severely impairs their ability to relate to others.
35% EXP[]
When reaching 35% Exposure Level, terrible paranormal events occur around the Monstruous. Inexplicable coincidences become a constant in their life, no longer mere fantasies.
Their body starts to resist the commands of their own brain, occasionally trembling or moving on its own, and at other times, refusing to obey their will.
40% EXP[]

#_Maelstr0m*, a Energy Monstrous
When reaching 40% Exposure Level, as the humanity of the Monstrous is replaced by the Entity, the changes in their body and mind intensify.
The Monstruous becomes even more resistant to the chosen Element, but also further worsens their performance in activities they were already struggling with.
50% EXP[]
When reaching 50% Exposure Level, there is more of the Other Side than Reality within the Monstrous. At this degree of exposure, they further align with the element they have a connection to. The next time they Transcend, the Monstrous will develop Affinity with that element.
65% EXP[]
When reaching 65% Exposure Level, like a parasite, the Monstrous feels the Entity walking through their entire body, making them its dwelling.
The Monstruous becomes even more resistant to the physical effects of their Element, but due to the advanced degree of their transformation, they become less sociable, more terrifying, and increasingly less sane.
99% EXP[]

When reaching 99% Exposure Level, the Monstrous has been transformed into the perfect habitat for the Entity residing within their body and mind. At this point, they are almost entirely a monster.
The Monstruous gains even more resistance to their Element, and the effects of their daily ritual become permanent (even though they still need to perform it to avoid feeling hunger and thirst), becoming irrevocably incorporated into their body and essence.
At this stage, the mind and body of the Monstrous are on the brink of being completely consumed by the Other Side. The transformation is complete, and what remains of their humanity hangs by a thread, with their sanity reduced to a critical state.
If a Monstrous goes insane at 99% EXP, they permanently become an Other Side creature.