Souei hails from the Ogre tribe, surviving a village-destroying attack alongside five others, including Benimaru and Shion. After initially confronting Rimuru due to misunderstanding, he allied with him to defeat the Orc Lord. The group then pledged eternal loyalty, evolving into Kijin when Rimuru named them. Souei became a cornerstone of the Jura-Tempest Federation as Rimuru’s Minister of Intelligence, commanding the espionage unit Kurayami. Originally an Ogre, he possessed a muscular build, dark bluish-gray skin, dark blue hair covering one eye, a single white horn, and prominent white canines. His evolution into a Kijin reduced his height to 180 centimeters, yielding a lean frame and calm demeanor resembling a late-teen human male. Shuna designed his dark-blue attire for optimal espionage efficiency, balancing stealth and mobility; it remained unchanged through later evolutions. Stoic and confident, Souei displays chūnibyō tendencies, embracing his ninja role with theatrical intensity. He executes duties professionally, eliminating threats to Tempest without hesitation or bias. His loyalty to Rimuru is absolute—he nearly killed a Lizardman for perceived disrespect toward his master. He values competence, mentoring subordinates like Souka while feigning ignorance to tease her admiration. He avoids Shion’s lethally poor cooking, humorously mimicking Rimuru to call her a "half-wit secretary," which she interprets as praise. Establishing Tempest’s counter-intelligence network within months, Souei thwarted threats like Dwargon’s spies, though magical surveillance requires aid from Shuna or Diablo. He intercepted Glenda Attley’s assassination plot against an Englassian prince—designed to frame Rimuru. After defeating Glenda and learning she was cursed into compliance, Rimuru removed the curse, and Souei accepted her as a subordinate. Relationships shape his interactions: - His bond with Benimaru transitioned from retainer-lord dynamics to equal rivalry and friendship under Rimuru. - He maintains a childhood friendship with Shion but considers her brutish and inept. - He teases Ranga by professing a preference for cats or mocking his popularity. - During Rimuru’s clash with Hinata Sakaguchi, Souei stalled Lubelius’s templars; his "torture" of Captain Litus inadvertently sparked her crush. In lighter contexts like the Slime Diaries spin-off, Souei reveals a fondness for cats, contrasting his severe persona.