A religious or spiritual practice evicting demons, from a location or within a possessed person. Formally being done by an Exorcist.
We see them as people wearing long robes and beating the demons out by speaking or yelling gibberish in a very dramatic way. At least, that is what we think they do. The "long robes" thing..., that's kinda optional. But the "beating the demons" one..., that's a whole different story.
Walking among us, yet invisible to our common eye, they search for Demons, strange and horrific shapes, who are disrupting the supernatural balance between our world and the other, whatever satisfaction they gain from it.
Once found, with incredible effort and equipped with their own set of abilities, as strange, if not, stranger than their enemies, eliminate their demonic foes to prevent any major imbalance to their world.
Not every day is a triumphant win for these invisible warriors, as there are days when lives are lost, at a great cost.
They work in secrecy, not a trace, to protect our world from theirs. To them, this... is Exorcism. And they, who are tasked in doing so, risking their lives for the lives of others that never knew they exist, these... are the true EXORCIST.