Nobuko Sasaki (佐々城 信子, Sasaki Nobuko?) is a lecturer at a university in Tokyo. She is the Azure Apostle and former accomplice to the Azure King, her lover, and attempts to ruin the Armed Detective Agency after her lover's death.
Sasaki is a young woman of slim build with pale skin and dark brown eyes. She has straight black hair that reaches her mid-back, and long bangs across her forehead brushed slightly to the right.
She wears a pale, cream shirt under a white bolero, a knee-length, light grey skirt, black stockings, and black low heels. During her visit to the cemetery, and later her death, she wears a plain white kimono.
While Sasaki initially seems a kind, friendly, and a rather patient woman, she is more than meets the eye. An accomplished woman in the criminology field, she's remarkably intelligent and skilled in her field of expertise, giving her an especially profound understanding of people. A resourceful woman, she succeeds in manipulating a number of infamous criminals from behind the scenes, leaving few tracks and no way for her victims to track her down.
Having no friends or family to turn to, Sasaki devoted herself to the Azure King's ideology, admitting to having no strong ambitions of her own, instead of appearing to cling to her lover's instead. Consequently, when the Azure King contemplated suicide after failing to change the corrupted government from the inside, Sasaki shows a surprisingly ruthless, drastic side, being the one who arranged many of the Azure King's terrorist attacks. This further emphasises Sasaki's intelligence, manipulating the situation from the background and allowing her lover to 'fulfil' his ideals. She shared his belief that the law system is too flawed to give influential people their due punishments, and had no qualms with schemes that led to not only their deaths but countless other victims. To Sasaki, the end justified the means: punish the so-called 'nonpunishable'. For all her accomplishments and wit, Sasaki, ultimately, feels hollow inside since the death of her lover, the Azure King. Having devoted herself to another person's ideology, Sasaki essentially lost her reason for living after his demise. She exhausted herself in attempts to fulfil her lover's desires and sense of justice, which she herself acknowledges did nothing but hurt her in the end. With no one to truly blame, Sasaki directed her anger and grief towards the Armed Detective Agency, due to their involvement in the Azure King's death, as if she had no one to blame, she felt she'd lose her mind.
Nonetheless, Sasaki feels no joy nor sense of accomplishment in severely damaging the Agency's reputation. During her confrontation with Doppo Kunikida and Osamu Dazai, she expresses nothing but a hollow, exhausted sensation, reaching the end of her ropes in trying to fulfil the Azure King's ideals, noting the man never said he loved her to begin with. Her targeting the Agency stems from both resentment and desperation for something to live for, unable to live for her own desires. The victims who suffered because of her she viewed only as a means to an end.
Sasaki points out that she could never with an idealist, as she'd always come last compared to their ideals, and ultimately be left behind. To her, the idealism the Azure King and Kunikida shared inevitably led people like Sasaki to feel left behind, always put second to ideals that could never truly be reached. Ironically, it's that exact nature that drew her toward Kunikida, to the point where she attempted to confess her love to him in her dying moments, showing considerable conflicting emotions with her feelings towards idealists.
Although not an ability user, Sasaki is remarkably intelligent and composed, making her a formidable enemy for the Armed Detective Agency. Behind a friendly face, she has a ruthless, scheming nature to her that allows her to manipulate many unwitting criminals. In reality, she's the one who arranged the Azure King's many atrocities.
She is a lecturer at a university, Sasaki studies and specialises in criminology, having grown an incredible, favourable reputation for herself. Her skill and talent are so well-known and respected that even government officials have turned to her for investigating complex crimes. However, Sasaki harbours a darker life, being the Azure King's lover and accomplice. She dedicated herself to his ideals, by his side when he attempted to enter the political world in an attempt to bring justice to those the law couldn't touch. When this failed, the reality and depth of corruption nearly drove the Azure King to attempt suicide via gutting himself. Supposedly, Sasaki stopped him, but unable to watch him suffer, she came to the drastic decision to take 'justice' into their own hands, and is, in fact, the one who arranged the Azure King's many attacks herself.
Following the anonymous tip, Kunikida, Dazai and Atsushi went to an abandoned hospital, where they managed to save the kidnapped drowning Sasaki. She introduces herself and reveals she had no idea how she got there, but as she started drowning she heard other voices. The group went searching for some people, but as they found them, they couldn't save them.
Some days later, Dazai was with Sasaki in the hospital, when Kunikida and Atsushi came. She thanks them for saving her and reveals she stayed last night at Dazai's place, which shocks Kunikida and Atsushi.
When the agency learns about the bomb threat, Dazai was with Sasaki in a cafe. Kunikida and Atsushi then came and they openly discuss the bomb situation. Dazai asks Sasaki for her opinion and she knew a lot about the Azure King and guessed this was either he or someone related to him. She had revealed she was single, as recently broke with her boyfriend, and Dazai then tried hooking her with Kunikida, as he was her type and revealed Kunikida's type which upon learning it, she thought it was too much.
On the next day, she went to the cemetery where she spoke with Kunikida and revealed she lied to him and that her boyfriend had in fact died. She then left as said she had things to do. A bit later, she went to the abandoned hospital and shot Rokuzō in front of Dazai and Kunikida. Dazai had figured she was the girlfriend of the Azure King and she was the Azure Messenger, so he had called her there. She lowered her gun, knowing that Dazai can't shoot her, but Dazai then dropped his gun and the dying Rokuzō picked it up and shot her.
- The name Nobuko means "trust" (信) (nobu) and "child" (子) (ko).
- Nobuko's surname Sasaki means "help, aid" (佐) (sa) and "castle" (城) (ki).
- In real life, Nobuko Sasaki was Doppo Kunikida's first wife, marrying him despite her parents' rejection (her mother even encouraged suicide), but she ultimately divorced him five months after when faced with pregnancy and financial instability that the divorce left Kunikida devastated.
- Sasaki's eyes are green in the BONES anime.
- Bungo Stray Dogs Manga: Chapter 28.