Relikt Windows game

"In a world ravaged by an eighteen year long war, 2 decade's ago, now being divided by the clash between magic and technologie, a young thief named Victor has been burdened to
serve as a vital tool to save the world from an ominous ancient threat
returning from its damnation.
You are a thief born and raised in the swampcountry Samweyr which is one of the poorest land's there are. It has a lot of swamp, little population and a lot of poverty. After the bloodmoon wars those who are able to cast magic rule the people as it has always been. Those who can cast magic without being part of a royal blood line or priesthood get sentenced to death. (convicted for sorcery and witchcraft). The general public believes that the nobles are blessed by the gods, and those who can work magic in the lower classes are possessed by demons. Fear allowed them to control people. Technology however, the new machines allow the general public to be independent, to live without being controlled by those who can work magic. It is clear that aritocrathy want to undermine any effort the scientists make and studying mechanics and machinery is outlawed as herasy)

The truth is that all human beings, trained enough can cast magic, most would only be able to telepathically move a glass after decades of training, others are more potent. The more potent you are, the more connected you are to the spirit world (in lag of a better therm) so it is more likely that you can be possessed or corrupted by an evil entitie.
The protagonist himself has been possessed by a demon in a moment of pure hatred and sheer raged. He was setting the thugs who murdered his daughter on fire...with his bare hands. They burned down to the bones within seconds. In a night, in which all people close to the veil of ghosts have been recruted by a once prisoned demonic force gathering in the shadows, waiting to strike to pave the way for their demonic rulers. Only the demon corrupting the mind of Victor is facing a different goal as she suddenly discovers sympathy for her host... the two form a bond to stop the invasion and to save Victor's kind.

The first game in the series (if a series will spawn from this) plays in the abbey of murhakar where young nobles and kings are teached in the art of magic and where they study for their future roles as Aristocrats. The abbey is heavily guarded by the legion and overseen by a coven of elite mages. Even though the abbey grew into its own little state over the century's (think vatican) it has originally only built to hide a secret guarded by the coven pretending to be only in charge of the recruitment of mages.
Underneath the abbey, deep within a maze of cavestructures lies a huge inverted pyramid built by an ancient, long lost, civilisation.

Sunken in the ground within the millions of years that passed, this temple hides the only weapon needed to ban the invasive demonic force... and it can only be wielded by someone with demonic blood. (you guessed it)

Alright, grammar errors, typos and the likes can be kept free of charge. Thanks for reading.