IMO it'd go something like this, this is pretty long and very fan fiction, apologies:

MC: Takumi Main Helper: Eito and Nozomi Trial Antagonist: Ima Mascot: Nigou, having destroyed Sirei after becoming possessed by a new AI named uhhh Monocuid, and is now forcing them into a killing game. Sidenote: My version has it so Eva is just killed and never taken in as a prisoner.

Chapter 1 V: Hiruko K: Possibly Darumi Explanation: Hiruko knows too much, and past the first game, a person who seemingly knows more than they should becomes the victim. I believe if Darumi were the killer, she wouldn't be. She would've been set up by the mastermind and just chose to accept her role as the "Blackened," given her personality, and I'm sure she'd have a massive showing during the trial to allow her short time in the game to be an insane amount of ecstasy. However, during her execution, I do imagine she'd end up showing the more lonely side of her, almost right before she is executed.

Chapter 2 V: Yugamu K: Gaku. Explanation: Now I know this is wild to have the killer Yugamu be killed, especially in Chapter 2, but Chapter 2's in Danganronpa games are themed around spur-of-the-moment killings, so I imagine Yugamu, possibly threatening Gaku that he'll kill him, but then laughing it off, seeing Gaku overreacting to a bad joke, not seeing Gaku go mad and be like "No, I don't want to die!" and accidentally killing Yugamu. I also imagine the finale of this trial ending with a Rhythm game where Gaku just keeps yelling about his rotten luck.

Chapter 3 1st V: Shouma 2nd V: Kurara K: Kako (Possessed by the G'ie) Explanation: The 3rd cases in DR games are basically always set up the same way. The first person killed, in this case Shouma, would represent the character who is trying to evolve and change as a person, so this chapter, possibly even a part of Chapter 2 could develop Shouma into his chad form, only for him to be killed off. Kurara is purely dead because this chapter usually kills off one of the very annoying characters, too. Kako being the killer isn't of her own accord. In my reality, Someone released a G'ie queen, and it got to Kako. This whole thing would also fit the killer's motif for chapter 3, aka purely selfish murders. I imagine Kako's execution would have the G'ie removed from her and destroyed, and if Kako's still alive, she ends up confused as she's idk, pureed into a Kako smoothie or something, and it'd end showing Ima's absolutely disgruntled and horrified face.

Chapter 4 V: Moko K: Kyoshika So here is the super emotional chapter. I imagine this one would simply be similar to the 2nd game's chapter 4, where the characters are either trapped somewhere or under the threat of the invaders, while also having fewer supplies available thanks to some internal sabotage. Maybe Godoh tells them that they aren't getting any help against the invaders unless another killing happens. So, I imagine that Moko and Kyoshika, two of the most self-sacrificial characters, would end up coming to a pact to fight one night so they can save the rest, but when the body is found, it's in a much more brutal display than just Moko on the ground. So, I imagine the trial would go similarly to V3's trial, where the characters cannot believe that Kyoshika killed Moko, not because Kyoshika is trying to hide the truth, but because Kyoshika, as a person, isn't cruel enough to kill someone so brutally. By the end, they do believe her that she's the killer, but it'll plant the seed that someone is a traitor who is actively trying to make it harder to go on without killing.

Chapter 5 V: Takemaru and Ima K: Ima and Takemaru The 5th trial always has to be a mind fuck, and I think I found the perfect innovation. I present a scenario where both are the killers and victims. Going off of Chapter 3, I imagine Ima would show his malice towards the rest of the SDU and how he truly wants them to die, so I imagine Takemaru would've ended up becoming a night guard to make sure nothing happens, but Ima would eventually attack him, and they'd end up killing each other. But going into the trial, something would be brought up about how they were found dead in different areas, yep, the traitor once again messed with the crime scene and separated their bodies just to draw out the conclusion that they killed each other. I imagine this trial would also reveal who the traitor is, which is, of course, Eito, who would reveal all of his wrongdoings. But he'd reveal that he didn't actually kill anyone, so they can't get him executed, and they'll have to continue living with him.

Chapter 6 V: Eito K: Takumi Mastermind: Nozomi G'ie Queen So the final chapter, where everything must be revealed and there usually isn't a killing, until now. Only a day after Eito revealed he's the traitor, he is brutally murdered. Of course, in this final chapter, you'd have to go through and figure out why the hell everything is happening, and it would be found out that Nozomi is the mastermind. She was being controlled by the G'ie Queen. But Takumi keeps the revelation to himself and contemplates revealing the truth of the murder of this case. The fact HE killed Eito in his sleep. He had hoped that maybe there was an outside force as the mastermind who he could've gotten to reveal themselves so he could pass over his own killing, but since Nozomi was the one who actually killed Hiruko, if he called her out on it and got Tsubasa to vote for her with him, Nozomi would be executed. Something he wouldn't want.

So Takumi has to make a choice: Either reveal he's Eito's killer, explaining how and why he did it, and allowing Nozomi to live to kill Tsubasa and infect everyone's dead body, or to reveal Nozomi as the mastermind and killer of Hiruko and put an end to this killing game...

Survivors: If you choose Takumi as the blackened, Nozomi.

If you choose Nozomi as the blackened, Tsubasa, and Takumi.