Make the Demon Lord Understand!

Demon King regrets defeat! Seeing the simple appearance of the new hero who has appeared in the Demon King's castle, the Demon King is confident of a comfortable victory. However, before he knows it, he finds himself on the floor, his resistance futile as he is strangled and knocked unconscious... When he wakes up, he finds himself on a bed in an unfamiliar room... The Demon King has been fitted with a sealing col...