FoundationAkihiko and Mitsuru harbor no romantic feelings for the other because they are both character choices for the protagonist to date. Even so, I personally feel they would be a good match for each other outside the game's mechanics. Please note, though, this is obviously just my opinion. I know not everyone agrees with me! Because a romantic relationship between them is not canon, I don't intend to pretend it is by pointing at any little evidence possible. My intention for this page is to talk about how their current relationship could be a strong foundation for future romantic feelings. Naturally, I am also aware of the reasons why they wouldn't work as a couple as well. If you are interested in reading those opinions, head over to the complications section.
As I explained on the previous page, Akihiko and Mitsuru share a strong bond despite not being the best of friends. Such a bond arguably can serve as a foundation for a more intimate relationship to develop! Akihiko and Mitsuru have known each other for a long time and have shared the most experiences together out of the other members of SEES (alongside Shinjiro, of course). Further, they are the two seniors of the group and the members with the most experience--somewhat of a common identity/function. Having a history with someone isn't enough to form a strong bond, though. I think another factor that contributes to their relationship is how similar their personalities are. On a surface level, they are both mostly serious, focused, motivated and mature. Therefore, they typically have the same opinions when decisions need to be made. In fact, Akihiko is clearly surprised Mitsuru doesn't agree with him towards the end of The Answer! They just seem to be on the same page.
I feel the key trait which allowed the two of them to bond was not in their surface personality, though. Akihiko and Mitsuru are both very goal-oriented and more concerned with getting the task at hand completed than focusing on their emotions. Once they decided their initial reasons for fighting, they both compromised their relationships with others. They also compromised their own personal feelings. All that mattered was reaching their goal. Forming a normal relationship couldn't occur for either of them because they were not in positions to cater towards others or consider their own feelings. Therefore, working with someone who didn't understand this mentality would have cramped their style. Both parties would ultimately have been frustrated and the relationship would have been strained. Akihiko and Mitsuru did have the same mentality, however, so I think this is what allowed them to form a solid relationship without becoming very personal. It's really no surprise, then, they seem to get along so well. They were able to understand each other without divulging much of their hearts.
One last aspect of their actual relationship that contributes to a strong foundation is how much they care about each other. Of course, Akihiko's feelings are much more apparent than Mitsuru's, but I think she cares about him in her own way as well. Akihiko says she is a precious person to him that he wishes to protect. He supports her to the best of his ability and often tries to make her feel better in group situations when she is feeling guilty. Mitsuru worries about Akihiko's tendency to be reckless (therefore his well being) and is not afraid to scold him over it.
All together, Akihiko and Mitsuru have known each other for a long time, have experienced many things together, get along well, have similar mentalities and personalities and care about each other. Putting the game mechanics aside, they certainly have the foundation to become closer. The only things missing were the sharing of emotions and perhaps physical attraction. I personally feel their internal struggles were the largest road block to them being more intimate, though. They were both in a place where they couldn't consider a significant other, so it's not surprising nothing happened despite their bond. However, I feel those same internal struggles could also allow them to become closer if feelings were shared. Both Akihiko and Mitsuru carried enormous guilt and burden because of their past and know the pain of losing people they love. They both know how difficult it is to move past such strong emotions as well. In that sense, they would be able to understand and comfort the other better than most others. They already get along very well and seem to trust each other. Who knows what the future could hold if they were to finally completely open their hearts? ♥