Devil Is a Part-Timer!, Vol. 20 (manga)

BACK TO WORK After their life-and-death battles on Ente Isla, Maou and company finally return to Japan to resume their daily lives. But as they settle back into the mundane humdrum of peace, there are still mysteries left to be revealed. For instance—just how did the powerless demon boy known as Satan rise to become the Devil King in the first place?