Earth - Demon Hunter

Earth is placed overrun by invading monsters. These are known as demons, they originate from hell and have the sole purpose of trying to kill most anything in their path. They are elusive shape-shifting creatures that do not show their real form.   The only known way demons can die is by forced death, performed by a class of peoples known as exorcists. It is a glorious title, but being an exorcist is a dangerous and hard job.   However, this doesn't stop the title from being well sort after and the job being available to all peoples who can afford to train their children.   So, the Exorcist Schooling system was born, but after a few centuries a powerful demon rose through his ranks and opened a school of his own. Soon after the school's opening, every exorcist school was burned and attacked vigorously by local demons of all power levels: from Rank F to Rank B. It was a massacre. And the demons loved it.   Now this demon Principal and his Exorcist school are the only things between the demons and their goal.   The Apocolypse.