When Yuri wakes up after his first time using magic he finds out from Wolfram that Conrad and Gwendal have gone off to protect a human refugee village that is being attacked. Yuri convinces Wolfram to take him out to help. On the way they run into Adalbert who tells Yuri that it is humans that are attacking the town so it is a fight between humans. He tries to convince Yuri to come with him and leave the demons but Yuri decides he is going to help the demons. Yuri decides to become the demon king and when they return to the capital they hold a coronation ceremony. To complete the ceremony he has to stick his hand in a waterfall but when he does he gets sucked back to Earth.

With Morgif now in his possession, Yuri finds out that the sword needs to absorb souls for energy. Jozak tricks Yuri to participating in a gladiator event so he can absorb souls when people die. Yuri is forced into a colosseum fight to the death and when he reaches the field he finds out that his opponent is Rick, the apprentice from the ship they were on.

As Yuri, Wolfram, and Conrad leave the castle to some soldiers, Stoffel and Raven start their next move. During the investigation, Conrad orders Wolfram and Yuri to stay put in a building. Yuri drags Wolfram and the remaining soldiers to conduct his own investigation of the missing dragon gem. Yuri's action led to his own abduction by Stoffel's men. Now Conrad and Wolfram head to Stoffel's castle to rescue Yuri.

After Yuri studies and practices baseball with Conrad, the news of a demon stone being stolen perks Yuri's interest. Yuri sets off into the city to find the stone with Jozak, Conrad, and Wolfram. They find the missing Demon Stone in the hands of Rosetta and her family, but the family is using the stone's power to repair magic tools and restore magic to earn more money for food. Yuri then decides to help them to get enough food. While they were helping Rosetta, they found that some thieves are trying to reclaim the demon stone. That night they find out that the thieves kidnapped Rosetta's brother and Rosetta set off with the demon stone to exchange for her sibling. Yuri, Conrad, Wolfram, Jozak, and Günter arrive in time to get the demon stone and save Rosetta's brother. Conrad decides to let Rosetta use the Demon Stone for business.

A young girl shows up claiming to be Yuri's illegitimate child, and then tries to kill Yuri. Yuri, compassionate as always, decides to give the girl the benefit of the doubt and assures everyone that there must have been a good reason behind it.

Yuri is suddenly pulled back to the other world but instead of ending up in a water source as usual he ends up in a barrel of alcohol.

Ulrike reveals that the final forbidden box is on Earth. Yuri, along with Murata, Wolfram, Conrad and Gwendal set off to locate and bring the box back to The Demon Kingdom.

The Kohi and many animals are acting up due to the fear of all of the forbidden box's are gathered together. Yuri manages to gain their trust and calms them.

Shori goes to The Great Demon Kingdom by accident after the lake in Switzerland pulls him in. He asks Yuri to stop the ceremony of the forbidden boxes and questions the Original King's decisions.