@mutha3: Doesn't he explain his reasoning for sending the threats in the scene where the Jester Social Link transforms into the Hunger Social Link? I'd have to go back, but I'm almost certain Adachi actually wanted to see people suffer, which is why he was actually annoyed when they were being saved, despite still enjoying his little game of "cat and mouse".
Ah, so they tried to address it in the Golden.
I haven't seen that scene, so I can't really comment on how they tried to fill that plot hole. In vanilla P4 though, that explanation doesn't fly.
The figure appears after almost every murder and says things to the effect of "Dammit!" and "why does this keep happening?!". Adachi's supposed to know why its happening and according to his dialogue he loves it.
As for that letter: Its never explained why he sent that. I interpreted that as Adachi deciding to shake things up, since he doesn't really have any motivation for doing what he does beyond "im cray-z!!!!!!--"... I don't really see how those letters would lead to someone dying anyway.
@Brodehouse: Ethan's blackouts can be explained if you ask the psychiatrist the right questions. His answer is basically, "You were in a coma for 6 months. You're brain is fucked up and shits gonna happen that we can't predict."
That doesn't explain why Ethan shows up in the exact same place everytime with an origami in his hand. In fact, it doesn't explain shit. Maybe if Ethan's Blackouts involved him falling unconscious, then that explanation would make sense.
It doesn't really make sense for that figure in the fog to be Namatame, Adachi or Izanami.
The figure progressively becomes more angry as people are rescued from the TV world....which Namatame should be happy about, Izanami has no stake in anyone dieing either way, and Adachi thought the cat-and-mouse game between Namatame and the IT team was fun enough to watch that he threw in Mitsuo to keep it going.
Really, Its just a plothole. Just imagine that its a random dude who curses about some inconvenience when one of those scenes pops up.