Midwood

The monster-slayer troops known as 'Sretu' no longer function as they used to, and humans have become the monsters' prey.

Jin Cheong-Do, who has been living in a world full of monsters his entire life, uses a legendary item known as "Midwood" to turn back time in order to kill the one known as Ian, the cause of this whole mess...

(Source: Naver, translated)