Chapters 3-12 of the light novel introduce a cast of characters and establish the initial setting and conflicts. The story begins with the formidable mercenary Ash, a seemingly immortal and incredibly powerful human whose terrifying appearance belies a pure heart and exceptional domestic skills. He is known for his overwhelming combat abilities, including a cannon mounted on his shoulder, and a face so frightening it causes even monsters to recoil, though demons find him handsome. Ash, an orphan who was sold to a mercenary guild, desires a quiet life after his military service.
The narrative then introduces Rebecca, a young, vulnerable dragon who sustains herself by converting happiness into magic. Currently a child, she relies on the Archdemon Rui to fulfill her wishes. Rebecca is prone to loneliness and cannot survive without companionship. She is naturally friendly and drawn to kind individuals like Ash.
The plot thickens with the arrival of Irene Bateman, the sensible youngest daughter of the Bateman family, who seeks to re-hire Ash. Irene is revealed to be Ash's childhood acquaintance, originally intended to be a male friend, but changed to female to soften the story's darker elements. She is accompanied by her subordinate, Bell Wickerman, who, despite her role as a tsukkomi (straight man), is a dangerous individual with a penchant for cute things and a desire for Ash's baking and Rebecca's maternal role.
The story flashes back to the year 1776, detailing a brutal war between the Holy Kruger Empire and the Norman Republic. Ash, then seventeen, is instrumental in the Kruger Empire's improbable victories due to his superhuman strength and resilience, earning him the moniker "Armor Crusher." He single-handedly decimates enemy forces, causing widespread panic. Despite his effectiveness, Ash feels unsuited for mercenary work, yearning for a peaceful life. His contributions are ultimately stolen by corrupt nobles, leading him to retire and purchase a dilapidated estate in Crystal Lake, a former noble resort town devastated by war.
Upon arriving at his new home, Ash discovers it is haunted. He easily dispatches the ghosts with a "spirit-repelling paddle," revealing his unusual ability to combat supernatural entities. Soon after, he hears a child's cries from a well and rescues Rebecca, the young dragon, who has fallen in and injured her wing. Ash, despite his initial hesitation due to his past experiences with wild creatures, decides to care for Rebecca until her wing heals and he can find her "Dragon Rider." He demonstrates remarkable domestic skills by preparing a poultice for her wing and sharing his meager food.
That night, Rebecca, using her dragon magic, secretly repairs Ash's entire estate and surrounding farmland overnight, transforming it into a beautiful, flower-filled haven. Ash is astonished by this sudden transformation.
Meanwhile, Irene, investigating the Kruger Empire's recent string of victories, learns of Ash's extraordinary abilities and his retirement. She travels to Crystal Lake, accompanied by Bell, to recruit him. Upon arriving at Ash's miraculously renovated estate, they witness his incredible farming techniques, which involve destructive, yet effective, "special moves." They also encounter Rui, an Archdemon who claims to be Rebecca's subordinate and explains that dragons need constant happiness to survive. Rui, who feeds on misfortune, cannot directly care for Rebecca but entrusts her to Ash, warning him of the dragon's fragility.
The narrative culminates with Irene, Bell, and their guards witnessing Ash's overwhelming power and the presence of a dragon, leading to panic among Irene's men. Irene, despite her initial fear and the revelation of Rebecca's true nature, is impressed by Ash's gentle nature and culinary skills, particularly his ability to create adorable marzipan figures. Bell, smitten with Rebecca and Ash's creations, declares her intention to marry Ash. Irene, realizing the gravity of the dragon situation and Ash's unique capabilities, decides to stay and find a way to recruit Ash, despite his reluctance and the overwhelming presence of Rebecca. The chapters end with Irene and her retinue establishing a temporary base in Crystal Lake to negotiate with Ash.
