Kikuko Kawakami (ChuKiku)

Chuya and Kikuko met when they were fifteen. Seeing him with Dazai on her way to do a task, she questioned what he was doing which Dazai replied with it being "top secret~". Taking note of her, Chuya could only watch her as she gave a shake of her head and muttered something the line of being dramatic. Noticing his stare, Kikuko simply gave her name and apologized in advance for any of Dazai's antics before scurrying off before he could respond. At his questioning look, Dazai just replied with the fact that she's shy. The two would meet again once Chuya joins the mafia as both were under Kouyou. Kikuko apologizes for Dazai's behavior once again and Chuya simply asked her why she keeps doing that. She responded with him being quite annoying when toyed with people and it became a habit of her's to apologize to however happened to be on the end of it resulting in them both agreeing with the statement. Chuckling at how quickly they clicked, Kouyou informed Chuya to 'not hesitate in finding Kikuko if he needed any assistance' causing her to clam up. This would start their friendship as Kikuko could often be found with Chuya when not with Kouyou as she found his friendliness genuine and comforting unlike Dazai who only liked to tease her for her shyness. Because she was with Chuya for the most part, she would also find herself with Dazai was quite skilled in keeping the blue eyed male from falling for Dazai's jeers. Likewise Chuya is quite good at reading her save for Kouyou and Dazai, being one of the few the girl will actually respond to and not bothered by her bluntness.

During the Dark Era, they are shown to be rather close with both showing romantic interest in each other. With Kikuko working under the male during this time, it was obvious to everyone with a pair of eyes that Chuya cared about her more than what could be considered caring for his subordinate. She worked with him during Dragon's head rush and was there to reassure him of his humanity when he finally got a hold of the information he was looking for. He is particularly protective of her when they are in battle together and is noted to worry about her when she sent out for days at a time. Kikuko herself finds Chuya's overall presence extremely relaxing and while she's not as shy as she was when she was younger, she still prefers his company over others and tends to sought him out when coming back from any mission she's assigned. The two would later quietly enter into a relationship as they saw no point in beating around the bush in regard to their feelings.

At the current point in the story, the two haven't really change. While they tend to keep their relationship private due to Kikuko's shyness in this regard, the two can be seen sneaking in affectionate here and there.