Reborn as a Monster at the Start

Human beings think that they have become the masters of this world. Human pride has opened Pandora's box. The appearance of monsters has caused the murder of all life in the world. Humanity has been defeated step by step. Finally, humans have sealed the monsters at the cost of their strongest men's lives and treasures. The power left after the monsters were sealed has turned the monsters into monsters. The power of the monsters is too terrible. Humans have to use artifacts to kill most of them. The monsters ran away, and the artifacts exhausted their power and turned into fly ash. - Is this really the case? This novel and its characters are purely fictitious. Any similarity is purely coincidental and should not be imitated.