Nagi Saeki

Tetsu Akatsuki’s close friend and roommate. His older brother, Naoya Saeki, had taken care of him in place of his parents who were too busy with work to come home. As such, he’s very close with Naoya and eventually joins TOKKOH.

Appearance
Nagi has blackish-blue hair with light blue eyes. He wears the TOKKOH uniform, with a policeman cap which has a blue band. His hair is styled after Naoya with his bangs falling over his forehead and curled slightly at the ends. His uniform consists of the button-up coat, likewise to what many of the other TOKKOH officers wear.

Within Tetsu and his special story, he wears an elementary school uniform that somewhat represents a sailor uniform, consisting of a teal ribbon-like accessory and dark blue attire. His hair was swept more to one side although it still appeared similar to Naoya's hair style.

Personality
Nagi is honest and impulsive, (as said in his character card) he does not hide his feelings and lives without protest. He also relies on Naoya very much but hates him for hiding his true feelings against his parents. Nagi is also hell-bent, he does things without any further evidence mostly parts wherein he doubted Mitsuru for his brother's murderer. It was also stated on his card that "it was easy to make his lines" and "we were saved by him" because Nagi cannot lie.

Background
Nagi originally disliked Naoya, being sick of his 'good boy' personality when in front of their parents. He was also unable to fathom what 'family' meant, interpreting it to be as the people that just gave him a place to live and food to eat.

When he had woken up as a child, he had heard his parents speaking and looked through a crack in the door, seeing that his father had just punched Naoya for not being the top of the class and saying he was pointless since he's receiving the highest education. He only observed the situation and didn't do anything.

After Naoya had finished his 'discusion' with their parents, he had noticed Nagi who had been eavesdropping. Naoya told Nagi to go back to bed and if he did, he wouldn't tell anyone that Nagi was being a 'bad boy' for staying up late. However, Nagi ignores Naoya's instructions and starts repeatedly shouting about how he hates Naoya whilst crying and grabbing onto Naoya, refusing to let go. Naoya attempts to use all sorts of measures to get Nagi off him, trying to pull him off and even saying 'Who do you think you are? I'm telling you to just get off me.' Nagi refuses and ends up getting into a physical fight with Naoya while still pinning him down, punching him while screaming and crying. Naoya ends up doing the same, crying and fighting back which is later revealed to be the first time Naoya cried. Later, the two are caught by their parents and are separated with some assistance from their butlers, the adults interpreting it as a fight that just started for no reason. Nagi thinks to himself that he doesn't know why he started the fight but believes it was because he just wanted to completely break Naoya's facade in front of their parents of him being a 'good boy' by seeing him act brashly. Afterwards, Naoya apologises for hitting Nagi even though he was an older brother but Nagi asks him how he feels with Naoya responding that it felt like a burden had been lifted off his chest and thanked Nagi. The scene returns to the time as TOKKOH officers where Nagi is raging at Mitsuru who continues to tease him, with Nagi admitting that he does love his brother although wishes that he chose a better best friend. On the other hand, when Tetsu moved into the 'Saeki' household, Nagi was the first to greet him, claiming that Tetsu must've been his new 'minion'. Despite Tetsu protesting, Nagi insisted that Tetsu was his minion until Naoya interrupted the both of them, scolding Nagi for acting that way. After being reprimanded, Nagi suggested that the he and Tetsu go to the kitchen to take the cookies as he could smell them. On their way there, Tetsu begins to panic as his memories begin resurfacing and Nagi snaps him out of it, saying that if there's something troubling it, he can avoid it, likewise to how he runs away from his butler when he (the butler) is upset with him.

The scenes returns to their time together as TOKKOH officers where Nagi had just returned from the market and presents Tetsu with cookies. Tetsu takes it gratefully and thanks Nagi, purposely calling him 'Boss'. Nagi becomes embarrassed and tells him to quit it, saying that it was a long time ago although admits his guilt since he was the one that started it.

Character Gallery Card 2
"He is a partner of the main character. Maybe because of the main character is quiet, Nagi became a noisy person. In the previous setting of the characters, he was supposed to be cool but now he's totally different. We think this is better because Tetsu is so quiet. Not to feel a heavy atmosphere in the story, the partner shouldn't be cool anyway. He is impulsive and hell-bent. He can't hide his feelings. Many of the characters have some kind of constraints and dark history behind them. Nagi is the only person who lives without any protest. So we hope you can sense the goodness from Nagi when you get at/or get saved by him. He doesn't tell lies, so it was easy to make his lines. We got saved by him."

Trivia

 * Despite his means of battle being pistols, he has shown the ability to use a sword as shown when he begins attacking Tetsu near the last stage.
 * Nagi's first name (凪) is calm. His surname Saeki is written with two characters, 冴木, with 冴 is to be skillful, and 木 meaning tree or wood.""