I was just thinking about it since she had been on the brain recently and… I’m fairly convinced Adachi’s least favorite Investigation Team member is Naoto. He takes it the worst by far when she survives, giving Yu an unusually pointed remark about how he shouldn’t be involved in the murders immediately after her rescue, and expressing exasperation when he looks at where her body should have turned up on the foggy day.
He literally never expresses the same agitation in any other foggy day event, and never reacts with such open hostility like he does with any other character’s rescue. Hell, she likely was the reason for the first letter, since it was before Nanako came into the public eye, so he couldn’t have known she was going to be targeted by Namatame yet. He also explicitly singles her out over the other Investigation Team members when expressing anger that Yu came alone instead of with the others in the arcanum reveal scene.
You could argue that his anger is more related to the IT clearly being active after he’d supposedly gotten away with everything thanks to Kubo, but he states in his confession that he explicitly did not want Kubo to take the fall for his actions, and heavily implies Namatame is the one he wanted to frame, so Naoto’s actions were a favor to Adachi, initially.
However, Naoto did this insanity on purpose. She basically duped him and now Adachi has another Persona-using professional detective chasing him. He’s probably not over that! Not to mention she’s just a kid who basically speedran her career thanks to her grandpa’s support while he got here the normal way despite Adachi being stated to be academically brilliant and a skilled detective in his own right, which sparks some (for once) understandable jealousy in him. And this guy holds some serious grudges—ask Namatame… not to mention she’s the one to call him out on exactly what gave him away.
