TV-Series
Description
Soei, an Ogre survivor of a tribe massacre in the Great Jura Forest alongside Benimaru and four others, initially formed a temporary alliance with Rimuru Tempest to defeat the Orc Lord. Following this victory, Soei and the remaining Ogres pledged permanent allegiance to Rimuru. Rimuru's act of naming triggered Soei's evolution into a Kijin, granting a more humanoid form with enhanced capabilities and marking the start of his service within the Jura-Tempest Federation.

As a Kijin, Soei assumed the role of Minister of Intelligence and leads the covert unit Kurayami. His duties focus on espionage, counter-espionage, and information gathering for Tempest. He built an effective intelligence network capable of thwarting spies from nations like Dwargon, though purely magical espionage sometimes necessitates aid from experts like Shuna or Diablo. His loyalty to Rimuru is absolute, provoking fierce reactions to any perceived insult against his leader.

Physically, his Ogre form possessed dark bluish-gray skin, dark blue hair covering one eye, a single white forehead horn, visible white canines, blue eye-shadow, and a lean, muscular build optimized for agility. His evolved Kijin form presents as a lean, calm young man approximately 180 centimeters tall. He retains the dark blue hair and blue eyes but loses the prominent horn, gaining a more refined, collected demeanor. His attire, designed by Shuna for espionage practicality, features a dark blue color scheme that is neither too tight nor loose. This appearance remained consistent through later evolutions.

Soei exhibits Chunibyo traits, embracing his ninja role with extreme seriousness, occasionally amusing companions. Despite this, he maintains a stoic, confident, and ruthlessly efficient exterior during missions, strictly separating delusions from duty. He values his long-standing friendship with Benimaru, noting their relationship became more equal after shedding the master-retainer bond. His composure falters only when Rimuru is disrespected, often manifesting as a "creepy smile."

His abilities center on stealth, assassination, and intelligence gathering. Key skills include "Parallel Existence" for creating clones to multitask and rotate sleep, "Spatial Manipulation" for instantaneous movement, "Universal Perception" for heightened environmental awareness, "Ultraspeed Action," and "Thought Acceleration" for rapid analysis. He wields "Sticky-Steel Thread" for combat and binding, alongside proficiency in dual blades and swordsmanship honed under Hakurou. He possesses numerous resistances, including nullification of spiritual attacks, pain, abnormal conditions, and physical damage. Former abilities "Shadow Motion" and "Malice Perception" were absorbed into his Ultimate Gift, "Tsukuyomi, Lord of Moonshade," granted after Rimuru's ascension to Demon Lord. His mystic arts focus on thread manipulation, employing techniques like "Mystic Thread Slash" and "Mystic Puppet Thread." His equipment includes unnamed dual ninjatō, kunai, and a Walther P99 handgun.

Within the slice-of-life context of "The Slime Diaries," Soei's fondness for cats is highlighted, revealing a softer aspect beyond his intelligence duties. This spin-off portrays his participation in Tempest's daily activities and festivals, reflecting his community integration.