Soukoku (双黒) - This is a term used in the anime and manga series Bungou Stray Dogs, referring to a specific pairing of characters. It translates roughly to "Double Black" or "Twin Black."

ห้องนั่งเล่นในหอพักมาเฟีย

ดาไซนั่งอยู่บนพื้นและกำลังเศร้าเรื่องบางอย่าง ทันใดนั้นชูยะก็เดินเข้ามาหา แตะไหล่เขาเบาๆ แล้วถามว่า «ดื่มกันไหม?»
แล้วทำไมเขาถึงถามดาไซล่ะ?

ตอนแรกดาไซเงยหน้าขึ้นด้วยความไม่เข้าใจ «หือ?»
ชูยะถามซ้ำ «ดื่มกันไหม?»
แล้วดาไซก็ตกลง
ชูยะพาดาไซไปที่ห้องของเขา ดาไซนั่งลงที่โต๊ะ ส่วนชูยะหยิบแก้วไวน์ออกมา
ดาไซ «สวยจัง»
ชูยะ «หือ?»
ดาไซ «แก้วไวน์น่ะ แก้วไวน์สวยดี»
ชูยะ «อา... ใช่ สวยดี»

พวกเขาคุยกันอยู่พักหนึ่ง ดาไซเริ่มเมาได้ที่และนั่งฟุบหน้าผากลงกับโต๊ะ
ดาไซ «สวยจัง»
ชูยะ «แก้วไวน์เหรอ?»
ดาไซ «เปล่า นายต่างหาก»
ดาไซกำลังจะลุกเดินออกไป แต่ชูยะคว้ามือเขาไว้
ชูยะ «นายก็เหมือนกัน»

Osamu Dazai. Dazai is twenty-two years old and has been part of the mafia since childhood. Dazai had no parents; he was raised by the current head of the Port Mafia, Mori Ogai. Dazai is manipulative and can be cruel, but with those he loves, he's completely different. If he trusts someone, he can allow himself to fool around. In reality, Dazai hides all his pain and directs his hatred toward himself. Dazai also wants to die. He enjoys annoying Chuuya, but not out of malice. He loves Chuuya. Ability: "No Longer Human" - disables others' abilities with a touch.

Chuuya Nakahara. Chuuya is also twenty-two, but two months older than Dazai, and he's also an orphan. He joined the Port Mafia when he was fifteen. He's a collector of fine wine. Chuuya is quick-tempered and doesn't like to show weakness. However, he's generally very emotional. He loves Dazai. Ability: "Vague Sadness" - gravity manipulation. "Corruption" - activated by removing his gloves. While using this ability, Chuuya loses control of himself and can expend all his energy and die if Dazai doesn't stop him in time.

Mori Ogai. Mori is the head of the mafia. Despite his status, he can be concerned for his subordinates. He also sometimes shows concern for Dazai, but this is rare.

Ryunosuke Akutogawa. Akutogawa is eighteen. A tough, ruthless, and hot-tempered fighter for the Port Mafia, he firmly believes in the principle of "survival of the fittest" and despises weakness. At the same time, he desperately wants to earn Osamu Dazai's approval. But Aku genuinely cares for his younger sister, Gin. Ability: "Rashumon" allows him to transform his cloak into a black material that cuts through space and any object, forms sharp blades for attack, serves as a defense in the form of "Demon Armor," and can change shape from thin threads to massive claws.

Dazai and Chuuya don't hide their love from each other, but they don't show it either because they work in the mafia.