Lev Lainur Flauros hailed from an ancient magus lineage predating Christianity, cursed 3000 years prior by Goetia to serve as the vessel for the Demon God Flauros. This curse destined him for possession by Flauros, awakening in 2016 to oversee humanity's incineration. Lev displayed prodigious talent, attaining the Fourth Rank (Fes) at the Clock Tower by age twenty and later directing a research building within the Eleventh Archaeology Faculty. He cultivated an approachable persona as a protector of humanity, a calculated deception masking his true nature as a malignant sadist who deemed humanity without a future. Lev manifested three distinct personalities: Lev Uvall, a research-oriented magus indifferent to lineage and politics; Lainur Gusion; and the dominant Mr. Flauros. During the "Clock Tower 2015" events, Lev Uvall committed suicide through dismemberment to prevent his transformation, causing the remaining personalities to mutually annihilate and inadvertently disrupting Goetia's scheme. Within the "Fate/Grand Order" timeline, Lev joined the Chaldea Security Organization in 1999, crafting SHEBA, the Near-Future Observation Lens. He manipulated Chaldea's director, Olga Marie Animusphere, fostering her dependency while secretly plotting humanity's end. During Chaldea's inaugural mission to Singularity F (Fuyuki), he betrayed them, planting bombs in the control room. The cataclysmic explosion killed most staff, critically injured 47 Master candidates, and seemingly killed Lev. He then Rayshifted to Fuyuki, delivering the Holy Grail to Saber Alter to perpetuate the singularity. After Saber Alter's defeat, Lev reappeared, unveiled his betrayal, and used the Grail to trap Olga Marie within CHALDEAS, subjecting her to an eternal state of death. In Singularity Septem, Lev attempted to annihilate the Roman era by summoning past Roman emperors as Servants to forge the "United Roman Empire." When this alliance collapsed, he incarnated into the Demon God Flauros and battled Chaldea. Defeated, he summoned Altera using the Grail to destroy Rome, but she killed him instead. At the climax within Solomon's Temple, Lev resurfaced, detailing his 3000-year affiliation with Goetia and confirming his role in triggering the Incineration of Humanity upon his 2015 awakening. He transformed into Flauros to halt Chaldea's advance but was slain. Regenerating, he summoned additional Demon God Pillars before being overwhelmed by Heroic Spirits answering Chaldea's summons. Physically, Lev appeared as a forty-year-old German man of Aryan descent, typically attired in a green formal suit, top hat, and boots, with unruly reddish-brown hair extending past his shoulders. As Flauros, he manifested as a towering tendril adorned with rows of red eyes. His magecraft encompassed wind-based spells channeled through a cane and manipulation of "Imaginary Numbers" for dimensional storage. As Flauros, he wielded vastly amplified destructive magic.