Beelzebub-jou no Okinimesu Mama.

Landing a job in the Demon King's service is the fulfillment of Murin's lifelong dream. For as long as he can remember, he has looked up to the ruler of the demon realm with unwavering reverence, envisioning a being of terrifying majesty, commanding presence, and power beyond anything ordinary demons could comprehend. Now, having finally secured the coveted position, Murin steps into the halls of the royal castle ready to devote himself wholeheartedly to the legendary sovereign he has worshipped from afar. Yet the reality of his tenure proves to be nothing like he imagined. From the very first day on the job, Murin discovers that the Demon King is not the awe-inspiring paragon he built up in his mind. The distance between the lofty legend and the sovereign who actually rules leaves him thoroughly thrown off balance, forcing him to adapt to a working life far stranger than anything he could have prepared for. Torn between the idealized figure he has always admired and the unexpectedly different master he now serves, Murin finds his loyalty and resolve put to the test. What should have been a dream come true instead becomes a daily journey of surprises, as he gradually comes to know the true Demon King behind the myth—one unforeseen revelation at a time.