Exhausted from his training to become the next King, Yuri is looking for any distraction he can find. Celi, meanwhile, unexpectedly announces that she is getting married. Later, Yuri devises a plan to stop Wolfram from trespassing into the King's room... sounds easy enough, but it requires some monster slaying!

Yuri Shibuya just can't catch a break. First, his head is dunked in a toilet. Then he's transported to another world - where he finds himself king of the Mazoku's, a new race that expects him to lead them to war against all of humanity. And to top it all off, he's engaged - to a man!

On the way to the border village with Wolfram, Yuri and the others run into Adalbert, who tries to convince Yuri to join the human side. But it turns out that Adalbert has led the humans to the village to start a disturbance! Will this finally convince Yuri to become Maoh and put a stop to all this fighting?

In disguise on a luxury ship, Yuri, Conrad, and Wolfram continue their voyage to Van de Veer island in search of the royal sword Morgif. But when pirates board the ship and raise Yuri's ire, can he keep from blowing his cover along with his top? And the sword of a demon king is going to have some nasty surprises of its own for our young hero!

A king's job is never done! The quest to fully activate Morgif isn't over. As hard as Yuri tries to feed his strange sword human energy without taking unnecessary life, the duties of a King sometimes require unpleasant sacrifices. Can Yuri reconcile his true feelings with his new job?

Yuri and the three brothers set out to rescue Yuri's impostor, who is supposedly in the country of Svelera. Along the way, Yuri and Gwendal are separated from the rest, only to be arrested for being elopers! Have they been lured into a trap? Only an abandoned bride and the true imposter will tell!

Yuri's forced proximity to Gwendal (thanks to the handcuffs) leads to a better understanding between the two. But they are soon separated after their trial for "elopement." Yuri is sent to a labor camp consisting of only women, many of whom had been caught trying to elope with their Mazoku lovers. The injustice towards these women and their children sends Yuri into Maoh Mode bent on retribution.

Everything seems to have calmed down for the Maoh - until Yuri returns to his castle and finds that he has a love child! Is he even old enough to have fathered a ten-year-old girl? If that wasn't bad enough, the tiny terror tries to kill Yuri and he twists his pivoting foot in the process.

Due to the return of Morgif, Van da Via Island has turned into an inferno with the restarting of volcanic activity. With this sudden occurrence, the Big Cimaron army quickly withdraws. However, the children of royal families, who are being held as hostages by Belar, are left behind amidst falling rocks. Yuri and his group head out to rescue them, but the rescue efforts, hampered by flying sparks and burning, falling trees, prove to be extremely difficult!