There is no such thing as immortality.
Even if there were, there would be a heavy price.
And that is where the Dark Knights were born. Demonic like immortal warriors who plagues villages and defeated army singlehandedly with the price of feeding with blood. Until eventually, they became a legend inself.

Cedric Gregory has been living his carefree life of a traveling physician in a small village out of bounds to the world with the hopes of trying to escape and forget his dark past. But all comes to an end when a group of knights brings in a sick man for treatment.
And soon, Cedric finds himself running away to save the life of a girl from being a military experiment only to discover that the past he was trying to escape from, has deeper roots which he can't ignore.