The story begins with the protagonist, Reiss Heivil, brutally defeating a character named Cain Roglin in a duel. Despite Cain's broken limbs and inability to fight, Reiss continues to assault him, even stepping on his head. A female student, Cain's childhood friend, protests, citing a rule that the duel ends if the referee deems a participant unable to continue. The referee, a teacher, is initially frozen but eventually declares the duel over, awarding victory to Reiss. Reiss, however, delivers a final kick to Cain's face before leaving, earning the teacher's ire and a summons to the staff room.
Reiss is then joined by two beautiful girls, Lilia and Rurua, and their maids, one of whom, Serena, sharply rebuffs the protesting female student. Reiss reflects on his identity: he is the eldest son of Duke Heivil, possessing immense power, wealth, status, talent, and ability. He is aware that he is the villain from a game called "Lord of Justice," or "Los," which chronicles the protagonist Cain's growth.
The narrative then delves into the game's lore. Cain, from a lower noble family, harbors a strong sense of justice and a desire to eliminate "evil" nobles who trouble his father. Reiss, conversely, grew up in a powerful ducal family, constantly wary of those seeking to exploit his family's status. This led him to distrust others, even family, and to believe that any means, including villainous ones, are acceptable to achieve his goals. The game, played from Cain's perspective, naturally cast Reiss as the antagonist. Despite his overwhelming strength and popularity, Reiss was destined to be killed by Cain.
The story shifts to Reiss's reincarnation. He awakens in darkness and, after a period of confusion, realizes he has been reborn as Reiss Heivil. Thirteen years have passed since his reincarnation. Driven by a desire to avoid his fated death at Cain's hands, Reiss aims to obtain what the game's Reiss could not: companions, a lover, and overwhelming power to shatter his destiny. He has diligently trained, mastering swordsmanship and summoning a demon named Leviana at age six, significantly boosting his abilities. He conceals his true strength to avoid attracting unwanted attention.
Reiss's ducal family is approached by a merchant selling a magic item that enhances training. Reiss, finding the item useless, dismisses the merchant. When the merchant persists, Reiss reveals his knowledge of the merchant's illicit dealings with the Farm Count family, extorting them through threats of cutting off their crop exports. Reiss then has Leviana execute the merchant.
Reiss is then tasked by his father, Duke Gold Heivil, a highly capable individual who is also the Prime Minister, to inspect the ducal territories. Reiss, accompanied only by Leviana, begins his inspection in disguise. They visit a large city, a residential area, and finally a slum. In the slum, they overhear a group of cloaked men plotting to destroy the Heivil ducal family. Reiss intervenes, and Leviana swiftly dispatches three of the attackers using a blood magic spell called "Bloody Lance." Reiss interrogates the remaining attacker, extracting information that reveals the plot was orchestrated by Marquis Lesser, who harbors a grudge against Reiss's father for being appointed Prime Minister instead of him. The Marquis's plan involves using the sister of a girl Reiss encounters in the slum to frame the Heivil family for neglecting a saint.
Reiss encounters the girl, Rurua, and her sick sister, Lilia. He offers them his protection. Lilia, initially hesitant, is revealed to be one of three saints in this era, possessing the power of healing. Reiss uses his healing magic to cure Lilia, confirming the information he obtained. He then explains his reasons for offering protection: Rurua's determination to protect her sister, Lilia's status as a saint, and their appearance.
Two weeks later, Reiss, Lilia, and Rurua are traveling together. Lilia is contemplating her decision about becoming a saint, while Reiss continues his inspections. During their travels, Lilia confesses her feelings for Reiss and chooses not to become a saint, opting to stay by his side as his lover. Reiss accepts her, and their relationship deepens. Rurua, initially surprised by their intimacy, eventually expresses her desire to join them.
The group arrives at the final city for inspection. During their market visit, Lilia and Rurua actively participate, influencing Reiss's purchases. Reiss overhears Rurua and Leviana discussing his tendency to be lenient with women he cares for. Later, Reiss is invited to a clandestine slave auction. He suspects the auction will involve slaves, a practice becoming increasingly regulated. He attends the auction, accompanied by Lilia, Rurua, and Leviana.