Fifteen years have passed since the start of the war. A small band of warriors have set out to defeat the Demon King, but when the Hero, all alone reaches his target, gets more than what he expected.

The Demon King’s plan is met with heavy resistance from uneducated humans. The Hero gets to witness and the darker side of the Head Maid and questions the validity of the grand plan.

With the first harvests coming in and things settled in the village, the Demon King visits a convent for the next step in her plan. But the nun she meets there has a past with the Hero, and isn't happy to see them together at all.

Several months had passed since Hero's departure and Female Knight moved to the villa to teach swordsmanship to the Crimson Scholar's students. A member of the Trade Alliance, Young Merchant, pays a visit to Crimson Scholar and she introduces to him another crop then unknown in the Human Realm, corn, claiming that it will help boost mankind's food production even further. Before leaving, he proposes to Crimson Scholar much to her embarassment. With half a year since Hero left to the Demon Realm, the Queen's anxiety increases, unaware that he has made use of his teleportation skill to return regularly to the villa behind her back, a fact only known by Chief Maid, to whom he confesses that he refrains to meet her out of his drive to become useful to her. Meanwhile, the southern nations are assembling a huge naval force to recapture Aurora Island, the only territory in the human world in possession of the Demon Army.

At Gateway City, a huge city in the Demon Realm occupied by the Humans, Hero, addressing himself as Black Knight, saves a Demon barmaid from being harassed from Crusaders and learns from her how most of the Human army have mistreated the Demons since occupying the city except those who guard the Eastern Fortress. Meanwhile, the expeditionary fleet sent to recapture Aurora Island is a disaster no thanks to their incompetent commander the White Night King when Demon Krakens destroy most of the fleet with only a few survivors, including the Winter Prince, whose father is killed saving the White Night King. Back in the Southern Nations, most of the Southern leaders are disgusted with White Night King, who refuses to take responsibility for his failures and tries to blame it on the late Winter King.

The Crimson Scholar offers plans to the Winter Kingdom to capture Aurora Island. Hero liberates Gateway City by terrifying the nobles to an extent which makes them flee the city. The commander flees after selecting the new commander of the city, of which this new commander decides to make Gateway City a new government that allows humans and demons to live together. The Crimson Scholar unfolds the plan to create an artificial land bridge linking the Winter Kingdom and Aurora Island. After capturing the beachhead, they learn that the Ice General is currently awaiting to be besieged, with an army of 8,000. However, the Winter Kingdom only has an army of 12,000; when normally three times the amount, 24,000, is necessary to successfully siege a castle. However, Hero arrives with a grand army of 9,000 of the best soldiers the Humans have. These soldiers are actually those who had fled the Gateway City, led by the previous commander of Gateway City to aid the Winter Kingdom.

As the second summer arrives, the Winter Kingdom has improved significantly with the Crimson Scholar sending one of her students, the Merchant Youngster to help the Winter King. After training with Female Knight and tasting Younger Sister Maid's carbonated drink, the Hero heads back to Gateway City as the Black Knight to attend a festival. While feasting with the Eastern Fortress General, the Fire Dragon Princess, daughter of the Archduke Fire Dragon, arrives much to Hero's chargin as the Princess considers herself as the Black Knight's wife. Realizing time is running out for her, the Scholar brings Hero along with Elder Sister Maid, whom has become her apprentice, to the Iron Nation to show a new invention that will improve the education of the humans, the Printing press.

Young Merchant pays a visit to the Crimson Scholar's villa and by her instructions, Elder Sister Maid tries to impersonate her with the magical ring, but is unable to deceive him. Hero then intervenes and takes him to the Demon realm where he shows him that the now liberated Gateway City became a thriving metropolis inhabited and ruled by humans and demons alike and have the Fire Dragon Princess hold a banquet to them, where he offers him the right to explore the commerce in the city in exchange to help in his and Demon King's efforts. Meanwhile, the Queen has a short meeting with Female Magician at the Royal Library, before entering into the ritual chambers, instructing Head Maid to kill her should she loses her sanity in the process. Back at the villa, Female Knight offers herself to be properly knighted by Hero in a sign of offering him her eternal loyalty, to which he reluctantly accepts.