TV-Series
Description
Isaac, formerly Araki Takafumi, worked as a carpenter in the real world and experienced several short romantic relationships before the Catastrophe transported him into Elder Tale. There, he rose to become the guild master of the combat-focused Black Sword Knights, adopting the alias "Black Sword Isaac" as a Human Guardian-Gladiator. He possesses a tall stature, maroon hair, and often wears a confident, contemptuous expression.

Initially elitist and antagonistic, Isaac enforced strict recruitment policies for his guild and dismissed the sentience of the People of the Land. He purchased EXP Pots from the exploitative guild Hamelin, considering them essential for maintaining his guild's competitive edge against rivals like D.D.D. His confrontational nature emerged during the formation of the Round Table Alliance, where he openly challenged Shiroe's authority upon discovering Shiroe controlled the Guild Center and access to Adventurers' assets. An early hint of integrity surfaced when he orchestrated a cleanup of Log Horizon's guild building using summoned Undines, interpreted as an apology for his earlier hostility.

Isaac's character developed through his Round Table Alliance responsibilities. He coordinated border security during the Libra Festival and later protected Raynesia during a sabotage attempt. Relocating to Maihama marked a turning point; tasked with training the Earthling knight order Glass Greaves, his harsh methods led to his relief from duty. However, his assignment to mentor Duke Sergiad Cowen's heir, Iselus, revealed greater depth. Though initially reluctant, Isaac grew to respect Iselus's dedication and formally agreed to educate him in Adventurer ways to prepare him for leadership. This mentorship culminated in Isaac thwarting an assassination attempt on Iselus during the heir's birthday banquet, exposing Westlande-backed Foxtail assassins.

Politically, Isaac aligned the Black Sword Knights with Eastal following the Round Table's collapse, opposing Eins's appointment as Duke of Akiba. He supported Raynesia's campaign in the Akiba General Election, contributing to the New Round Table Council's formation. Despite moving his guild's base to Maihama to fulfill obligations to the Cowen family, he joined this new council.

Isaac's personality blends a rowdy, battle-loving exterior with strategic thinking. He relishes combat, demanding opponents "fight like you're gonna kill me," yet approaches battles methodically. He exhibits notable administrative incompetence, delegating paperwork to his subordinate Rezarick and lacking familiarity with tools like PowerPoint. Despite maintaining a gruff demeanor, his interactions—particularly his reluctant but genuine care for Iselus and participation in strategic dinners with Krusty and Shiroe—demonstrate a capacity for loyalty and growth beyond his initial isolationism.