Some people guess that when this particular set of events ends, Allen and Kanda will leave the Black Order. But what if Kanda can't? Where is his original body now? What if he is not actually in his current body, but linked to his old one? If it is still in possession of the Black Order, then they've got authority over him and have all along.
How many years have passed? It's been approximately 20 years at a minimum, since his current body had to mature, but who says he was put in it immediately after his death?
...
And about the Mysterious Lady Friend ...
The relationship is still murky - but let's assume that it was either romantic or trending that way.
Did he ever tell her how he felt? He is, of course, no good at perceiving emotions in others, and he pretty much sucks at expressing his own, unless it's anger.
So, what if she's gotten used to him being dead? What if she married someone else? Hell, perhaps I'm getting ahead of myself - what are the chances she's still alive?
...
Kanda's gone bonkers (took him long enough), but what's with whatserface going "Alma shouldn't want to kill him, so stop Kanda" ...? (Paraphrasing there, clearly.) I seem to remember several occasions where AngryAkumaAlma said he hated Kanda, wanted him to die, etc. etc. etc. AngryAkumaAlma just shot the poor kid in the chest twice with those weird stick things! Uh, hello? Violence usually does not indicate that AngryAkumaAlma doesn't want to kill someone.
I am (not so) secretly hoping that Kanda kicks Allen around a bit before he somehow comes to his senses. I am also hoping he remembers to stick his one arm back on.