Kaname Date works as a detective for the Tokyo Metropolitan Police Department's Advanced Brain Investigation Squad. Six years before the present, an undisclosed incident caused him to lose his left eye and memories, leading him to adopt the name "Kaname Date." This event involved a prototype Psync machine that swapped his consciousness into a body formerly belonging to Saito Sejima. His original identity was Hayato Yagyu, an orphan who suffered childhood abuse, became an assassin for the Kumakura crime family, and later turned detective.

His artificial left eye contains Aiba, an advanced AI serving as investigative partner and perceptual augment. Aiba facilitates neural linkage for shared thoughts and emotions, plus photographic documentation and communication functions. When Aiba detaches, Date's left eyelid remains closed. His appearance features light brown unkempt hair and heterochromia: a green natural right eye and a yellow artificial left. He consistently wears a black trench coat with purple accents, a purple turtleneck, a black vest, purple gloves, and holstered weaponry.

Professionally, Date specializes in "Psyncing," entering suspects' subconscious dream states ("Somnium") to extract information. He balances a serious, justice-driven demeanor with compulsive lechery, exhibiting numerous sexual fetishes like bondage dynamics and pornography obsession. He attributes accelerated reaction times near pornography to a childhood snakebite coinciding with his discovery of adult magazines, though others doubt this claim. His relationships include a father-figure dynamic with ward Mizuki Okiura, close friendships with colleagues like Boss and Renju Okiura, and a combative rapport with otaku-character Ota Matsushita, whom he blackmails during investigations.

Non-canonical "Dreamy Drama Theater" shorts depict Date in comedic chibi scenarios reflecting core traits: hosting an absurdist quiz show, aggressively interrogating Ota Matsushita in a restaurant, and supervising Iris Sagan's disastrous driving lesson that escalates into danger. These highlight his professional authority, deadpan reactions to absurdity, and protective instincts.

His backstory involves childhood trauma in an abusive orphanage, fostering a vigilante ethos. After extrajudicial killings, the Kumakura family forcibly recruited him as assassin "Falco" until the body-swap incident reset his memories. Post-amnesia, he retains moral complexity, leveraging blackmail for investigations while showing deep loyalty—evidenced by adopting Mizuki and enduring Aiba's sacrifice to save others. Current cases involve rescuing internet idol Iris Sagan from extraterrestrial abduction and solving "The Third Eye Game" escape challenge, utilizing new "Escape" mechanics alongside Psyncing and traditional investigation.