From Google Translate:

[No Escape from the Demon King's Castle—Go on the Offensive and Turn the Tables on Adversity!!] In a chaotic world torn by conflict between humans and demons, a human named Ren finds himself taken prisoner by the demonic forces. His life thus far has been nothing but a constant flight, but within the Demon Realm, he is forced to confront a harsh reality: without resistance, there is no survival. Just moments before his scheduled execution, a stroke of quick-wittedness allows this cornered mouse to bite back against the cat! And somehow—against all odds—he begins to carve out a place for himself within the very walls of the Demon King's castle... The curtain rises on a fantasy comedy of shifting fortunes, proving that true potential shines brightest when one is pushed to the absolute brink! + More