Yuri Briar/Relationships

Yor Forger
After both of their parents died at an early age, Yor was the one who raised Yuri during his childhood despite living in poverty. Because of this, he has developed a sister complex and will do anything to keep Yor safe, to the point of suspecting her husband of being an enemy spy. In addition, Yuri is very possessive of his sister, always wanting to spend time with her at every opportunity and getting irritated when someone else is around, usually Loid and Anya. He holds a deep appreciation for Yor, as seeing her work bloody all for his sake in their youth motivated him to become a successful man, and he vowed to protect his last living relative.

He is unaware of Yor's secret job as an assassin. Likewise, he hides his job as a Secret Police officer from her.

Loid Forger
Yuri and Loid have a very complicated relationship, as Yuri is jealous of Loid for being his sister's husband without being told, so he tends to act rudely towards him, even having a one-sided competition with him over Yor's affection. Although he has admitted that Loid is a handsome man with great skills and a good career, Yuri still thinks he is unworthy of being with Yor and would even go to such circumstances to hurt him if he ever found out that Loid harmed or did something bad to his sister.

While he has baselessly suspected him as a spy, Yuri is unaware of Loid's true identity as "Twilight."

Anya Forger
Yuri first meets Anya in person when Yor calls him over to tutor the girl for her midterm exams. Neither of them has a good impression of the other due to Yuri's dislike of Loid and his child, while Anya gets creeped out by Yuri's overly obsessive thoughts about his sister. Using Yuri's love for Yor, Anya is able to persuade him into tutoring her seriously, and he eventually shares his motivation for studying when he was younger, teaching her that knowledge is power. Although Yuri later stomps off in frustration when Anya fails to learn anything, the study session makes him realize that he needs more knowledge in order to keep his sister and country safe.

Later, he learns to tolerate her when Yuri (along with Loid and Yor) tells Anya that lying is wrong, despite them all lying about themselves. He has also risked himself to save Anya from the Red Circus' bus hijacking, as he knows that losing the child would break his beloved sister's heart.

SSS Lieutenant
Yuri's senior in the SSS. He looks out for Yuri and urges him to take care of himself more, telling him to stop drinking and be careful after hearing about him overworking. He keeps Yuri in check to stop him from acting hastily and is aware of his sister complex, which he tells him to get over it. After Yuri collapses while Yor is out on a business trip, the Lieutenant nurses him back to health.

Dominic
Yuri's friend and neighbor from Berlint City Hall. Occasionally, Yuri has Dominic update him on how his sister is while he is out for work.

Camilla
Camilla had already an idea of what Yuri looked like by photos Yor showed her in their work, but they official meet at Camilla's house when she was teaching Yor how to cook and Yuri was called to taste on their results. At the beggining Yuri was doubting of her teaching skills and even got mad at her for being rude towards Yor, but later thought to himself that she might be a good influence for his sister after Camilla angrilly claims that it would be easier for Yor to break up with Loid than to give her cooking lessons.