TV-Series
Description
Bercouli Synthesis One, originally known as Bercouli Herlentz, is a foundational figure in the history of the Underworld, serving as the leader of the Integrity Knights and the de facto commander of the Human Empire's defense forces. His existence spans centuries, with a physical body appearing to be in his early forties while his memories and experiences stretch back approximately three hundred years. Before becoming a knight, Bercouli was a legendary swordsman and a rebel who despised the oppressive rule of the Axiom Church. He led a group of followers to the remote northern frontier and co-founded Rulid Village, where he acted as its first guard chief. His attempt to cross the mountains into the Dark Territory led to his capture by Administrator Quinella. She used him as a test subject for her experiments on Fluctlights, damaging most of his memories, and eventually transformed him into the very first Integrity Knight through the Synthesis Ritual.

In terms of personality, Bercouli is defined by immense self-confidence and a relaxed, almost casual demeanor, even in the most intense situations. He possesses a deep-seated pride as a swordsman, which makes him reluctant to rely on his weapon’s most powerful and unfair abilities. He is not ruthless; he shows a clear sense of care for his subordinates, particularly his disciple Fanatio, and holds a faint but persistent distrust of the Church's elders, though he continued to serve them for centuries, believing the Axiom Church was necessary to maintain peace in the human world. Despite having his memories suppressed, he retained his critical thinking and was one of the few knights aware of the Seal of the Right Eye that limited their free will, though he could never break it himself.

Bercouli's primary motivation shifts over his long life. Initially, as a human, he was driven by a desire for freedom from the Church's control. After becoming an Integrity Knight, his purpose was to serve as the absolute shield of the Human Empire, defending its borders from the Dark Territory. Following the fall of Administrator, his role evolves into a pragmatic leader and protector. He postpones recovering his own lost memories to focus on organizing the human army for the impending war, driven by the goal of preserving the next generation and the future of the human world. In the story, Bercouli acts as a major obstacle and then an ally. He first confronts Eugeo in the Central Cathedral's Great Bath, where his overwhelming power and the unique abilities of his sword nearly defeat the young swordsman. This battle is pivotal as it allows Eugeo to learn the truth about the Integrity Knights and forces Bercouli to begin questioning his own role. Later, during the War of Underworld, he becomes the supreme commander of the Human Empire Forces, leading the defense against the invading army and its gods.

Bercouli’s key relationships are central to his character. His most significant bond is with Fanatio Synthesis Two, his disciple and fellow knight. Their relationship evolves from a master-disciple dynamic into a romantic one, and it is revealed after his death that they have a son together. He also shares a paternal bond with Alice Synthesis Thirty, whom he trained and affectionately calls "Fräulein Alice," viewing her as a daughter figure. His rivalry and eventual respect for Eugeo, who manages to defeat him through clever tactics, serves as a catalyst for Bercouli's late-stage character development. In his final moments, he even conjures a memory of Administrator, suggesting a complex and not entirely hateful relationship with his creator.

Bercouli experiences significant development, primarily defined by his transition from a loyal enforcer of a corrupt system to a self-sacrificing hero who defies it. For centuries, he was a cog in the Axiom Church's machine, but after being freed from petrification, he takes full responsibility for the chaos left by Quinella's death. His ultimate development comes in his final battle against Dark God Vecta, the super-account controlled by Gabriel Miller. Knowing he cannot win through conventional means, he chooses to use his most despised technique, the Release Recollection that slashes the past, to land a fatal blow on his opponent. This act of sacrifice costs him his own life, but it solidifies his legacy as a true hero who gave everything to protect his world.

Bercouli's notable abilities are centered on his Divine Object-class weapon, the Time Piercing Sword. He is a master swordsman with centuries of combat experience, capable of matching and defeating all other Integrity Knights in sparring matches. His fighting style focuses on powerful, single-hit sword skills, which he has honed to compensate for the aftercast delay typical of such techniques. The Time Piercing Sword grants him two extraordinary powers through the Armament Full Control Art. The first is "slashing the future," which allows him to store the force of a cut in a specific point in space, which will then activate at a predetermined time, creating an invisible cage of slashes. The second and far more powerful ability is "slashing the past" or Release Recollection. This technique allows Bercouli to attack the log of an opponent's movement from ten minutes in the past. By striking where his target used to be, the system registers the hit on their current self, instantly reducing their Life to zero regardless of their defenses or durability. This ability is so absolute that Bercouli dislikes using it, as he feels it invalidates the effort and skill of both combatants. He also demonstrates proficiency in Sacred Arts for healing and can use Incarnation, the power of will to alter reality, to a high degree.