From age thirteen to eighteen Akihiko had known what he was doing in life. He did well in his studies, in his boxing, and at night he fought shadows in the dark hour.
The constants in his life have never been what he thought they were. He thought Shinji would always be in his life, but even now his biggest memory of September fourth is how Shinji ran. He spent his fifteenth birthday waiting without his best friend, and hoping he would show his face. He probably would have cried and been teased by Shinji for it, and he would have taken it over the ache that sat in his throat any day.
Mitsuru is a constant after that. The voice in his ear during battle, the one who is there on his birthday, the one who does help him with his studies. It takes awhile for them to break down the formalities she uses to interact with the world, and become teammates, but they were a great thing while they lasted, and even with the breakup of the team, as Shinji back disappears into the night, they are still both his best friends.
Once he adjusted, he had kind of felt that this was his life, and that he would be alright if he spent the rest of his life fighting in the dark hour. It had lasted for seven or so years, and it wasn't like they had made changes to it. Of course that changes. He's excited. Of course he's excited. And scared.
Even though this is for the best, change is scary.
It's only after he has graduated, and the dark hour has ended, that he wonders "what do I do now?"
And he doesn't have an answer, unlike Mitsuru who has a future planned, and he's lucky that he lived to get one, but for all the things he could do, he finds he wants to do none of them. For all Shinji talked about how he looked towards the future, he doesn't know what to do with it now that he has it.
He could go to college. He could continue boxing. He could do anything and yet what he ends up doing is running.
He keeps in touch with Mitsuru, because she is a constant, and to not do so would lead to her having him hunted down, and dragged to her so she could execute him.
He does odd jobs, makes a few friends, gets into a lot of fights, l learns to shape plates from clay, and crush a rock with his bare hands.
He comes when Mitsuru calls, and at twenty he ends up in the weirdest experience of his life. Interesting and fun, sure, but very weird. He gets it into his head that he wants to go to the police academy.
He doesn't stay in that either, but through it he meets Tamaki Uchida, who has a detective agency. She ends up hiring him, and he is surprised to find that he likes it.
It helps that she isn't an ordinary detective, and that while facing off against devils in the line of duty is not quite shadows, he didn't spend six years of his life fighting supernatural forces to lose it easily.
He's still a shadow operative of course, but he keeps Mitsuru up to date on his cases, and she sounds fond and resigned, and doesn't call him in when he is in the midst of a supernatural investigation.