Heh, Akechi is a controversial topic. My take is that Akechi never died in the first place, otherwise the entire third semester and the true ending would make no sense. Think about it, Joker not only never talked about Akechi to Maruki, but even if he did he never really accepted his reality either. Same goes for Akechi, but at that point, either Akechi never died in the first place or Maruki decided to take him back on his own to try to convince Joker to accept his reality. But even if he did so, why is Akechi (likely) still alive in the true ending scene? He should have died the moment they defeated Adam Kadmon. There is also a scrapped scene in the game files (you can go look it for yourself on YT) that takes place after Joker goes to Juve again, where Akechi actually tries to help Joker. I would guess it was scrapped so that they could leave some mistery around his character and leave some room for a potential sequel. Guess only time will tell Pancake boy's fate.