Kusuo Saiki, born to ordinary parents Kurumi and Kuniharu Saiki, manifested psychic abilities in infancy. Within two weeks of birth, he communicated via telepathy; by one month, he could walk and fly; at one year old, he performed errands. Childhood openness faded as he recognized the necessity of concealing his powers, resulting in a reserved adulthood. He possesses naturally pink hair, pale purple eyes lacking visible pupils, and wears green-tinted glasses to prevent involuntary petrification. Two antenna-like "limiters" on his head restrain his psychic abilities, removable solely during emergencies. Standing approximately 167.6 cm tall and weighing 52 kg, he typically wears the PK Academy uniform or homemade clothes. His transformation ability permits shifting into any living form—such as the female identity "Kuriko" or cat form "Psi"—requiring two hours per change and limiting power control in non-human states. His psychic powers encompass telepathy (effective within 200 meters, ineffective on simple minds or insects), telekinesis, teleportation (with a three-minute cooldown), hypnosis, clairvoyance (triggered by crossing his eyes), invisibility (lasting 10 minutes, negated by touch), elemental manipulation, size alteration, and bilocation. He utilizes psychometry through invisible gloves. Global-scale mind control normalized phenomena like pink hair or instantaneous injury healing. Without limiters, he could eradicate humanity within three days. Stoic and introverted, he avoids attention, primarily communicating telepathically. He prioritizes normalcy, achieving average exam scores and saving money for purchases like a coffee jelly maker rather than exploiting his powers. Selfless acts include sacrificing his favorite coffee jelly to aid others or resolving peers' romantic problems. He displays tsundere tendencies, covertly assisting friends while denying emotional attachment. Flaws involve pride in his abilities, pessimism, and gaps in common sense—such as susceptibility to online scams. Interests include reading, television, and anime, unaffected by telepathic spoilers. Initially friendless, he reluctantly formed bonds with classmates like Riki Nendou and Shun Kaidou during his second year. By the series' conclusion, he acknowledged them as friends, protecting them discreetly and nearly revealing his powers. A temporary power loss occurred via a limiter from his brother Kusuke, though his abilities resurfaced as his biology adapted. Post-series, fluctuating powers necessitated limiter reinstatement.