In Persona 1-2, personas can be used in the real world, and everyone can switch personas. In 3-4-5, personas can only be summoned in special worlds, and only someone with the wild card ability (which seems to be linked to the Fool's Arcana) can switch.
These differences are actually linked to Philemon's/Nyarlathohep's influence. In 1-2, their "bet" made Mikage-Cho and Sumaru a large-scale special world where personas can be used, and even cause a lot of people to become persona users. However, once their bet is settled at the end of 2:EP, the special world ends and everyone loses the ability to summon personas. The switching ability is also specially granted by Philemon himself, as even other people who have personas can't seem to switch them unless they've met Philemon.
The Last Battalion: Hitler's contingent of soldiers that escaped to Antarctica after WWII. Accused by Mrs Okamura.
- The case for: The Nazis also wanted to control the revelations in the Mayian Oracle and to keep their own existance from being leaked to the outside world. Though Kashihara had no desire to publish In Laqetti, they could still want some insurance.
- The case against: They literally did not exist until the publication of In Laqetti made them real through the power of rumours. There's no way they could've done anything ten years ago. Okamura is crazypants.
Junko Kashihara: Famous actress and the victim's wife.
- The case for: That Junko didn't care for her husband is a matter of public record. Trapped by a marriage to a conspiracy theorist husband who she thought was cheating on her...it's not hard to see how jealousy and rage could drive her to murder.
- The case against: There's no hard evidence connecting her to the crime scene. Just disliking someone isn't enough to build a murder case around.
Maya Okamura: Fellow teacher with Kashihara and co-conspirator to write down In Laqetti.
- The case for: Crazy and in love with Kashihara. On the testimony of one Detective Kuzunoha, Kashihara did not return said affections. Much like Junko, Okamura could easily turn to murder, and even has. She blamed The Last Battalion even though there's no way they could've done it; possibly delusions stemming from the dissonance of having killed the man she loved? She has means and motive.
- The case against: But possibly not the will. Before her final breakdown Okamura really did want to see Kashihara live and protect the world from the dangers in the Oracle. She has the capacity to be a murderer, but perhaps she didn't then.
Nyarlathotep: Anthropomorphic personification of humanity's dark side.
- The case for: He has the will, means and motive. Shapeshifting and teleportation alone assure an easy way to lure the victim and to get away afterwards. It was useful for Nyarlathotep for Kashihara to be dead for his plans, and he's never been shy about killing people for his goals.
- The case against: Yeah, he pretty much arranged the whole thing. The ultimate cause of Kashihara's death is entirely the fault of the Crawling Chaos. However, it's not certain that he did the physical deed himself. It's just not Nyarlathotep's style to reveal himself openly until the end. Influencing people towards destruction and using catspaws is more his line, leaving the physical act to one of the other suspects. Also, it's difficult to arrest and hold anthropomorphic personifications.
Akinari Kashihara: World history teacher at Seven Sister's High School, the victim.
- The case for: A wife that didn't love him and a son that was ashamed combined with a desire to save the school by preventing the Oracle make a strong case for a hopeless and desperate man ready to take his own life. The police at the time also ruled it a suicide, and hos ghost talks about 'wanting to be sure'.
- The case against: It is not in the policy of this court to take the word of ghosts as evidence, and police have been wrong before. It's possible, even likely, that Kashihara killed himself, but we must look at all possibilities.
Colonel Mustard: In the hall, with the revolver.
- The case for: After having murdered Mr.Boddy, the stubborn colonel noticed Boddy's associate Mr.Kashihara who met with Mr.Boddy regarding important business matters under the disguise of a business trip. Unfortunately, Mr.Kashihara saw just a little too much...
- The case against: Doesn't exist in the persona games, but this is a series in which Hitler was a Mayan Sorceror armed with the spear that pierced the side of Christ so this theory can be plausible.
There is much evidence for and little against most of the suspects. What other wild theories may exist among the court? Speak!
We've just been playing the PS version. Whereas in P3 universe, the adventure became known at some point, and was recorded in Innocent Sin Online.
- That...actually makes a lot of sense. What's the best way to prevent the people from Persona 2 from looking too deeply into those memories? Make them play it off as them being influenced by the game! Add in that Nanjou has the funds to push this game through, and it becomes even more likely!
- Also, the game is being cancelled because the plot is too crazy and implausible. But it served its purpose long enough.
He doesn't have a future in Persona, only a Shrug of God. This is more than likely.
- How can Tatsuya be Naoya's son? Tatsuya's 18, and P2 happens 3 years after P1 ends.
- And everyone gets a job and Brad becomes famous in 3 years.
- True. (Um, now what?)
- Actually, considering School Uniforms are the New Black, it's more than likely that they weren't at school in the flashback. How long ago was it? Where did Naoya go? They seemed about 17 in Persona, so around 20 in the flashback. This means Naoya could technically already have a son, or could at least be a father that year, so as long as it was 18 years ago, this part of the theory is correct.
- Except the returning P1 characters are all around 20 during the events of P2. (I'm pretty sure Nanjo and Elly are 20. Yukino might be a bit older.) Please don't make things up to support a jossed theory.
- Both of them have no social skills, are Ax-Crazy and have a similar appearance (though Mitsuo is somewhat neater and doesn't have the stalker's red eyes). Perhaps it's In the Blood?
- Jossed. He's an illusion.
- The stalker that appears in the dungeon was an illusion, but he was based on Eriko's memories of the actual guy.
IF Philemon is the representation of a part of the human subconcious then he is linked to Nyarlothep as he is linked to him, the only way to stop Nyarlothep is to kill Philemon, hence why his drastic actions, from erasing the people memory to taunting Tatsuya the whole point is to weaken and Seal Nyarlothep, Persona 5 will tell if this worked or not.
As of Persona 5, neither appeared in game, so if the theory is true, the world is safe from Nyarlothep's clutches for another day.
As Nyarlathotep recites the legend, blood poured endlessly from Jesus when he was stabbed. Nothing is said about the Spear doing that to anyone, just it doing that to Jesus. Therefore for the Spear to be that effective, Maya has to be Jesus Christ in some way.
- Adding to that, all of the Persona users on the Other Side are the hyper powerful shadows or superbosses. The Reaper is a former playable character.
- At first, this troper dismissed this theory, since the Kirijo Group's experiments on Shadows predate the events of both IS and EP, but then realised that the timeline split happened in 1989 at the latest. The Kirijo Group's experiments started 14 years before the events of P3 - 1995, six years into This Side at least. What's to say these experiments took place on the Other Side? After all, the events of P3 are impossible on the Other Side for obvious reasons, the whole "the moon is the physical shell of an Eldritch Abomination" thing could only be true if reality was as malleable as it ended up becoming in IS, and the IS-EP timeline changes long predate the actual events of the game; it could easily be the case that the experiments were impossible on the Other Side because it didn't have a semi-negated alternate timeline leaking into it, seeing as it was said semi-negated alternate timeline.
Youichi Makimura: Compared to the above, there's less to go on. However, what is known that he is a swindler that kept managing to dodge karma, tried to gain high status by joining the Circle, only to forced away from it and run for the rest of his life. This, remarkably, lines up well with that of Pyro Jack, a stingy Irishman who managed to con even the Devil to avoid Hell, but when he tried to enter Heaven was rejected and forced to wander for the rest of his life. Thus, Reverse Pyro Jack would be more than fitting for Makimura.