Kana will finally be able to "move on" when her life with Daikichi is over.She doesn't know why she stayed a ghost after she committed suicide, but the hints are that she did kill herself because she was desperately lonely. Now that she's found Daikichi, she will have "fulfilled" the reason for her having been stuck on earth as a ghost. By the end of the series, she not only says she has lost her fear of the living, but also that she has lost her fear of living. Significantly, Daikichi is wondering to himself if there is any way he could make Kana alive again when she looks over at him and says "It's great to be alive, isn't it." When Daikichi finally dies, she will be able to go with him. (I certainly hope so anyway because the alternative - that Kana will remain on earth as a ghost without her most beloved - is too heartbreaking to think about.)
Kana and Daikichi will live at the apartment forever.A reverse of the previous WMG. Instead of Kana moving on when Daikichi dies, he becomes a ghost and together they haunt the apartment, which may or may not have gotten some new residents by then.
That horrible old man was an angry ghost.He certainly didn't look of this world, and it would explain why he knew Utako was emotionally vulnerable and preyed on her while her defenses were down. He's just some hateful spirit that died angry and now spreads it around.
The body that Daikichi's team finds in the last chapter was someone close to Yaguchi.The story takes the time to point out that she's absent from work at the beginning of the chapter. Then, when she comes back at the end, her mood is considerably somber than usual and she's suddenly anxious to know what becomes of people when they die. When Inagawa reassures her that they don't disappear, she's so overcome with emotions that she burst in tears. With this happening in the same chapter where Daikichi and his team find a dead body, it's not difficult to believe that this can't be coincidence. Now, some people have theorized that she could be the body, while others think it was someone related to her. I lean towards the second interpretation as, 1) Yaguchi didn't have the "ghostly glow" that Kana and the dog ghost have been shown to have around them; 2) if she had become a ghost, she would have known that people don't disappear after they die (while Inagawa is confident in his answer because he knows that ghosts exist); 3) we don't know for how many days she had been absent from work, but when Daikichi's team broke into the room, the body had been there for long enough for the whole place to stink badly; 4) this would explain the line "Will all the things that you love also disappear?", of which an alternate translation could be "Will the fact I loved and was loved also disappear?".
The man from the government was related to Kana, and could even be her father.He takes the time to clean the huge nameless grave all by himself, and the way he speaks of the grave and of the people buried there, specifically at the end of his scene, sounds like he has some very personal reasons for doing so. From this point, it's not hard to suppose that someone he knows might be buried there too, and given The Law of Conservation of Detail...
Yoko and Kenji from the chapter "Stormy Date" are alternate-reality versions of Kana and Daikichi if she hadn't died
Kana will age along DaikichiOk, I admit: I just don't want them to grow apart as Daikichi ages while Kana remains the same. However, it is not utterly impossible either: if Kana discovered after ten years of being a ghost that a human could actually touch her, who says there isn't more Our Ghosts Are Different possibilities in this universe? Loving and being loved by Daikichi has made her "alive" enough to exist physically and generate warmth, it could make her "alive" enough to exist within time...