Seidou Takizawa launched his career as a Rank 2 Ghoul Investigator with the CCG, graduating second in his class from the Academy directly behind Akira Mado. This proximity fueled a gnawing inferiority complex and intense competitive drive. He idolized elite investigators like Kishou Arima and Koutarou Amon, collecting Arima's case clippings. Though earnest, Takizawa fiercely valued seniority and recognition, sparking conflicts when he perceived disrespect from peers or was outperformed by juniors like Juuzou Suzuya. He actively pursued field assignments to prove his worth, yet harbored deep fears of combat and death, suffering breakdowns in life-threatening situations. His assignment to the 20th ward involved investigating the Gourmet alongside his partner, Kousuke Houji. During the Owl Suppression Operation, Takizawa confronted the Aogiri Tree member Tatara alongside Amon. He suffered severe injuries before capture, leading the CCG to declare him dead. Aogiri Tree subjected him to extensive torture and experimentation by Dr. Akihiro Kanou, forcibly transforming him into an artificial one-eyed ghoul. This involved implanting Yoshimura's kakuhou, granting him an ukaku kagune, and enduring psychological and physical torment designed to purge human weaknesses. His mental collapse reached its nadir when Kanou revealed he had secretly fed Takizawa his own parents' remains, shattering his grasp on humanity. This ultimate trauma, combined with starvation and relentless torture, broke his mind and reduced his lifespan. As a ghoul, Takizawa adopted the alias "Owl" (T-Owl) and joined Aogiri Tree. His appearance transformed drastically: hair turned white and unkempt, nails and lips blackened, dark circles shadowed his eyes, and his left eye manifested a kakugan. He wore loose black robes bearing a hooded symbol. His personality warped into that of a merciless, erratic killer who embraced ghoul ideology, believing fear could only be conquered by becoming its source. He reveled in inflicting psychological and physical agony, often lecturing victims or mocking their philosophies. Despite his outward savagery, memories of his past surfaced, triggering moments of lucidity. His insecurities endured, focusing on his rivalry with Ken Kaneki (Kanou's perceived "masterpiece") and resentment toward the CCG for abandoning him. Encounters with figures like Akira Mado provoked intense shame, causing him to hide his face or flee. Takizawa's powers stemmed from his artificial ghoul physiology and inherited Ukaku kagune. He generated crystallized RC cell projectiles for ranged assaults and formed bladed limbs for close combat. He demonstrated rapid regeneration, capable of reattaching severed limbs. His unstable, incomplete kakuja initially manifested as a partial mask and shoulder blades, worsening his mental state and causing self-harm. Further development evolved his kakuja into a full owl-like mask and larger blades, stabilizing his combat style while retaining ferocity. This allowed him to fight evenly against Tatara and a kakuja-empowered Amon. Enhanced strength shattered concrete, while heightened durability withstood quinque strikes and Tatara's flames. A turning point arrived during the Rushima Landing Operation. Driven by a lingering desire for validation, Takizawa betrayed Aogiri Tree by killing Tatara, seeking approval from Houji and the CCG. When investigators rejected him and opened fire, he slaughtered them indiscriminately. In a subsequent rage, he nearly strangled Akira Mado but halted when she shielded him from Tooru Mutsuki's attack. Her selfless act and acknowledgment of Amon's determination to save him restored his sanity. He later joined Kaneki's organization, Goat, adopting a modified trench coat from his Aogiri robes. His ultimate fate after the dragon battle remains unknown, though reports suggest he hunts renegade ghouls as a half-kakuja.