Äs Nödt is a Quincy of the Wandenreich, holding the elite Sternritter designation "F" for "The Fear". Originally human, he suffered a prolonged illness that confined him to bed and medical dependency, cultivating a perspective of life as intrinsically agonizing. This existence bred profound dread of death and eternal damnation, rooted in religious conviction. Yhwach granted him power at death's threshold, transforming him into a Quincy spirit who joined the Wandenreich. His appearance includes long black hair, dark eyes with light pupils, and dark fingernails. He dons a modified Sternritter uniform: a hooded white cloak, multi-buttoned trench coat, black boots, and spiked fingerless gloves. A spiked black mask obscures his lower face, revealing exposed teeth and gums where lips are absent. During the second Soul Society invasion, his mask featured four spikes instead of five, and his coat added buttons. His Quincy: Vollständig, Tatarforas, reshapes him further—manifesting a Wandenreich-symbol halo, blood cascading from his eyes, and a midline-stitched cloak. Fully transformed, he becomes a multi-eyed monstrosity. Personality reflects cruel philosophical detachment, insisting instinctual fear is insurmountable. Arrogant in combat, he claims ownership over stolen abilities like Byakuya Kuchiki's Senbonzakura and voices loneliness without it. He mocks foes with macabre humor. Despite exuding terror, he harbors visceral fears: Yhwach's retribution and post-mortem hellfire. He rebukes allies for tactical errors, exemplified by criticizing Mask De Masculine's failure to seize Renji Abarai's Bankai. His combat prowess centers on the Schrift "The Fear", generating Reishi thorns that inflict instinctual, paralyzing dread upon touch—bypassing physical harm to corrode rationality into despair or death. He wields standard Quincy techniques like Blut Vene defense and Reishi manipulation, plus a Medallion to steal Bankai (notably Senbonzakura Kageyoshi). Tatarforas amplifies his power: victims within his gaze suffer magnified terror, and he spawns multiple eyes to encircle targets. In the first Soul Society invasion, he slaughtered low-ranking Shinigami before battling Renji and Byakuya. After stealing Byakuya's Bankai, he weaponized it to inflict psychological and physical torment, dissecting fear's nature while overwhelming the captain. Bazz-B's intervention saved him from Genryūsai Yamamoto's assault, and he later expressed shock at Uryū Ishida's succession by Yhwach. During the second invasion, he confronted Rukia Kuchiki to lure Byakuya. His fear initially affected her, but she nullified it by dropping her body temperature below living thresholds via Sode no Shirayuki. After partial freezing, he activated Tatarforas. Byakuya intervened, destroying the manifested eyes and revealing enhanced Shikai mastery—attributed to Äs Nödt's prior Bankai theft. Enraged, Äs Nödt fully transformed only to be frozen and shattered by Rukia's Bankai. In death, he confronted his lifelong terror of damnation.