The Knight Of Shadows TKS

In this world there are ferocious beasts who kill any human they see.
The human population was dropping like flies.
But then, special people were born with the power to use mana. These people were called mages. Mages had a wide variety of powers, but only the more powerful mages knew special abilities.
Because of the efforts of these people, after 50 years things were starting to go great for humanity. A school for mages was built to further strengthen earth’s defence against beasts.
However, a new enemy had arrived.