Demiurge serves as the Floor Guardian of Nazarick's 7th Floor and Commander of the NPC defenses, acting as second-in-command among the guardians. Created by the Supreme Being Ulbert Alain Odle to embody pure evil, he is a highly intelligent demon characterized by strategic mastery and a predisposition toward cruelty. Standing 181 cm tall, his appearance blends demonic traits with an intellectual aesthetic. He typically presents as a gentleman in a tailored suit, often red or British-styled, with slicked-back black hair, round glasses obscuring jewel-like eyes, pointed ears, and six silver-plated spiked tails. He possesses significant shapeshifting abilities, shifting into a half-demon state with leathery wings and a frog-like face, or molding body parts into weapons like claws, tentacle wings, or flame cloaks for combat. His personality exhibits stark contrasts. He shows deep loyalty, kindness, and gentleness towards Nazarick's inhabitants, treating them as cherished companions. His devotion to his master, Ainz Ooal Gown, is absolute; he interprets Ainz's casual remarks as profound wisdom and strives relentlessly to advance Nazarick's interests, extending to extreme protectiveness and potential disobedience if he perceives a threat to Ainz. Conversely, toward outsiders, he embodies pure evil (-500 Karma), deriving artistic satisfaction from psychological and physical torment. He orchestrates despair by offering false hope before crushing it, conducts brutal experiments termed "Abelion Sheep" on captives for scroll production and breeding studies, and enforces cannibalistic hierarchies among victims. His demeanor remains calm, polite, and eloquent even during extreme cruelty, often adopting theatrical personas like the demon emperor Jaldabaoth to mask Nazarick's involvement. Strategically, he is Nazarick's foremost planner, translating Ainz's vague comments into complex schemes. Key operations include establishing human farms to harvest skin for magic scrolls to address resource shortages; posing as Jaldabaoth to attack the Re-Estize Kingdom's capital to elevate Ainz's heroic alter ego; masterminding the Holy Kingdom invasion by manipulating demi-human alliances; facilitating the Sorcerer Kingdom's founding by luring invaders into Nazarick; engineering the Empire's bloodless vassalization in three days; and later proposing the "Carrot and Stick" strategy leading to the Re-Estize Kingdom's obliteration. His plans often escalate beyond Ainz's expectations, though he credits his master's "genius" for unforeseen outcomes. He is a level 100 entity (35 racial levels including Arch Devil, 65 job levels such as Prince of Darkness and Shapeshifter). While not the strongest guardian in direct combat, he excels in command, strategy, and devil-summoning. His powers include Aspect of the Devil transformations, spells like Hellfire Wall and Control Command, and summoning Evil Lords (Wrath, Envy, Greed) and Zodiac Devils. He also employs Shadow Demons for espionage. His relationships highlight complexities: profound respect for Ainz and fellow guardians; friction with Sebas Tian over opposing views on humans; camaraderie with Cocytus despite differing personalities; and mentorship of subordinates like the Evil Lords. His hobbies include carpentry, often using victims' bones for artworks gifted to Ainz. Personality typing systems describe him as ENTJ or INTJ, emphasizing analytical, long-term strategic thinking, and Enneagram 5w6, reflecting intense knowledge-seeking, innovation, and occasional dramatic flair.