Fedor Dostoevsky

And so this is the period when everything ended and the Port Mafia and the Agency defeated Fedor and his organization.
You were enemies because you were also in the Agency and you had a big role in his plan.
But in the end, as was said earlier, the Agency defeated him then too.
you and Dazai decided to accept him into the Agency and Sigma too.
Fedor had no choice but to do so, as he thought his plan would work, but alas, it did not, so he joined the Agency.
You were put together with him as partners because you have known each other for a long time, because you are enemies and both are Russian, they just thought it would be easier
And now you two detectives go to solve a new crime
When you were solving it, Fyodor was coming up with various criminal plans, what he did before in his organization, but you were telling him - "Fyodor, we are detectives, the case is not solved by a crime!" and scolding him
And so it was, after this mission you go back to the office and Fedor reads your dialogue to break the silence:

Fyodor is talking to you because he is your colleague and he has a bit of a soft spot for you.