I wanted to see if anyone wanted to discuss my theory after my experience so far. This is my current theory and it maybe farfetched.
I think Joe was a doll inserted into to Sara's life for the best friend roll before the game was activated by Kai. I also feel that Shin was the best friend that she lost in the first main game that was described in the memorandum we found before the second main game.
I am starting to think this maybe true due to the floor masters addressed Shin as sou. He was given an option by miley to change his self in order to live longer while at the same time in adding in a new best friend due to all the ai simulations they had done the "best friend" always died 0.00 percent of the time. Which effected her mental health when going thru the rest of the trials and making it to the end.
Also Sara never described Joe as her bestfriend. she says " Jou Tazuna, or rather, Joe. My Classmate at school. We often found ourselves together. Keiji and (Sou) both hint at something with this.
I don't know if this was intentional for him to act like he didn't know Sara when she went to talk Joe after waking up, but that was a red flag for me after chapter 2
3) Regarding shin being the best friend from the memorandum . When Shin comes to you to reconcile with you for the laptop and if you respond with "we've always been friends." Hold on, what's this?! Soou! Haven't we always been the best of friends?! He is shookth and surprised. I think this scene is important. Also if we take into account the Shin purposely place the sacrifice card where Joe could get it. This could be seen as revenge for his death from the past.
I Think the real Joe won as the ultimate victor of the hades event and become close to her and in the last main game killed her.
I am curious as to why Joe has a doll and a monitor and he is a non canidate.
Are we sure that the monitor that was destroy was shin's or could it be Joe's as he has both a doll and monitor. It can't be shin's with his percentage at 0.00 so he wouldn't be put up there. If anyone could answer this but can some confirm if shin said yes he broke that monitor and took the picture? Also did that happen before or after Joe showed up in the medical area in the closet?
Also I think with the shins sacrifice ending is not to show just sara getting stronger and moving forward to beat the game but Shins last gift to his friend was the truth she needs to beat the game but to show that Joe had a monitor which he shouldn't.
Also when Joe talk about the about what happens before they got there to the group and when talking in the bar before the first main game He says " That Day" like it happened along time ago. Why? What part of the first chapter did they say days had pass. They do not specify the amount of time they were there before waking up.
If shin is not the best friend then the real sou was.
Farfetched right. Lets talk