Assassin x Demon King

After seven years working as the renowned mercenary, The Inevitable Blade, Salvador has had enough. To seal his resignation, he tosses his sword in a river and vows to save 1,441 people, one for each life he took, in hopes that the smell of blood will stop chasing him to sleep. But the ex-king, Kain, who has a smile that could blot out the sun and who was supposed to be Sal's final job, starts to follow him around, and then Sal gets infected with a slow-acting poison for not killing him. Can he save the people he wants to save with only a year left? Can he keep it all a secret from Kain, who insists on worming his way into Sal's heart and life?