Souei hails from the Ogre tribe annihilated by the Orc Lord. Surviving alongside Benimaru and fellow ogres, he fled to the Jura Great Forest. Encountering Rimuru Tempest proved pivotal; receiving the name "Souei" triggered his evolution into a Kijin and cemented his permanent loyalty to Rimuru, initiating his service to the Jura-Tempest Federation. Rimuru's ascension to Demon Lord spurred Souei's further metamorphosis, first into a Youki and then a Kishin (Dark Spirit Ogre), earning him the monikers "Darkness" and "Lord of Shadows". Physically, Souei presents as a tall adult male, standing approximately 175–190 cm, distinguished by blue hair, blue eyes, and dark skin, with a single white horn protruding from his forehead. His signature attire is a blue-and-white ninja outfit complemented by black boots, reflecting his role as a covert operative. His personality remains consistently calm, reserved, and emotionally controlled, rarely displaying overt feelings. He maintains intense focus on missions and duties, exhibiting merciless efficiency against enemies, including a willingness to employ torture or lethal force under orders, though he sometimes exploits directive loopholes to instill fear. Deep loyalty to Rimuru and the Jura-Tempest Federation drives him, prioritizing their protection above all. He demonstrates gentlemanly conduct towards women yet remains largely indifferent to romantic pursuits, such as those from his subordinate Souka. Traits align with ISTJ or INTJ personality types and Enneagram Type 6w5 (Loyalist), highlighting his structured approach and reliance on authority for security. Souei's abilities focus on espionage, stealth, and combat: * **Thread Manipulation**: He generates adhesive, steel-hard "Nenkou Threads" (Sticky Steel Threads) to bind, cut, or control enemies, even spiritual entities. Techniques include "Demonwire Bind" for restraint and "Puppet Strings" for neural control over unintelligent monsters. * **Cloning and Mobility**: Initially, "Replication" produced six combat or spying clones lacking full aura capacity. Post-evolution, his Ultimate Gift "Tsukuyomi" (Moon King) granted "Parallel Existence", enabling multiple autonomous bodies sharing one consciousness. He navigates via shadows ("Shadow Motion") and teleports using "Spatial Motion" to previously visited locations. * **Sensory and Cognitive Skills**: "Magic Sense" gathers environmental data, translates intent across languages, and can overload ordinary brains. "Observing Eyes" detects magicule fluctuations. "Mind Accelerate" accelerates his thinking up to a millionfold, while Ultimate Skill users gain "All of Creation" for universal comprehension. * **Combat and Defense**: He wields twin ninja swords and employs "Secret Inspector" for instant kills via thread dissection. "Multilayer Barrier" provides automated, layered defense with minimal energy cost. "Cancel Pain" nullifies physical discomfort, and "Battlewill" converts aura into physical enhancements. * **Resistances and Evolution**: He resists coercion, pain, death manipulation, radiation, and power nullification. Following Rimuru's Demon Lord evolution, his magicule count surpassed Awakened Clayman, and his Ultimate Skill unlocked planet-level attack potency capable of bypassing world laws. As Rimuru's intelligence chief, Souei founded and leads the Kurayami (Shadow Squad), spearheading espionage and counterintelligence. He maintains a dedicated "Personal Line" thread for private communication with Rimuru. His duties encompass intelligence gathering, covert operations, and neutralizing threats to Tempest, leading him to decline participation in Tempest's Martial Arts Tournament to preserve anonymity. Key relationships define his interactions: unwavering loyalty to Rimuru, a competitive rivalry with Benimaru, and mentorship of subordinates like Souka and Ritus. Souka harbors unreciprocated feelings for him, which he acknowledges but does not return; he occasionally teases her, finding her reactions amusing. He shares tactical rapport with Diablo but actively distances himself from Diablo's hobbies.