Demon Sword Series
After the first world war, there was the first case that humans had faint hints of magic and that mythical creatures from all cultures were real. Humans were able to take all their negative emotions and cast it out to create a creature from said myths. Unfortunately this was only discovered after world war two. Although after that they were many researches to understand this strange new thing that humans could do. Discovering many things and then get schools to teach them. After a while people found out that they have no control on if they cast out their emotions or of the creature that they created, causing panic and more creatures. A task force was made to protect the people from themselves with the casted creatures as well as the real life ones from mythology. The trick is know which is which.