aitsf spoilers regarding my love for B-set. huge rant!
Unpopular opinion perhaps but I find B-set significantly more unsettling than "Boss" and "So." I wish we got more time with her because it so suddenly shifts from her being a HUGE suspect for both murders (and tied to the previous) to her suddenly being dead. With "So" it was uncomfortable but not at all unpredictable, most people figured he was hiding something so Saito's behavior in the Mizuki end route was not at all jarring. With "Boss" the build up was absolutely fantastic, but depending on the order in which you play the routes it seems impossible for her to be the actual killer. Assuming that is not the first route you do, highly unfortunate if so, then Boss's actions in Annihilation are highly out of character and therefore suspicious, making Saito's reveal highly satisfying but not at all out-of-nowhere. Her (his?) somnium is unsettling but not scary in the was B-set's was, and the answers to the chain murders are basically solved before the interrogation itself. In other words, "Boss" is a fantastic end-point, or Boss lol, to Saito's murder trail, but I do not find her genuinely unsettling or scary, just pure cold calculation. If I were to liken it to Danganronpa, it would be like a satisfying Mastermind reveal that makes perfect sense when all the pieces fall into place.
Now, continuing with the Danganronpa analogy, I would liken B-set to the Danganronpa 2 plot-twist, mainly with the chapter 3 killer. To keep it vague since this isn't a Danganronpa post, the reasoning and buildup for the death in that chapter becomes darker after the completion of the game since it provides more context; this is how I feel about B-set. Yes, Iris suddenly becoming a MAJOR suspect literally a day or two after hinting that she may be Date's adoptive daughter is extremely jarring, but it propels the story forward significantly and is very attention-grabbing. Her being a suspect (and, well, the killer) shows the fuckery of the game itself, yet I wish the game cooked with B-set a bit more before chopping her up. Yes, I know that we get all those Youtube videos on her channel and that there are bits of her on the Ota route, so this is of course coming from personal bias since I love her, but god I wanted her to be disturbing. Realizing after the completion of the annihilation route that Iris was dead since practically the beginning, that "she" was the cold uncaring killer all along, that was one of the most disgusting parts of the game to me. Because, that easily could have gone in a significantly different direction had Saito confronted Date at the end of Annihilation in Iris's body rather than Boss's. Imagine. Saito can imitate Iris pretty well. Imagine how disturbing it could have been had it led up to Iris being the overall killer, had her mind-fuckery of a somnium been the last one with the screaming, children's pictures, and blood? Had the face that stared at Date's been his daughter, of whom his memories were just starting to return, had Saito called him "Uncle"... that would have scared me to hell and back if I am going to be so honest. The juxtaposition of the two siblings staring at one another knowing that their previous lives and identities are dead, that could have been some powerful imagery.
In this AU-of-sorts, I would imagine that the plot builds up to Boss being the overall killer with Saito acting suspiciously as her, but ultimately Iris killing her on livestream (her personal stream and not in that stupid polar bear costume). Of course, disturbingly, I would imagine that Hitomi would not end up alive in this AU, but I love her too much to imagine what cruel things B-set could do to her. That, coupled with the fact that Saito killed her biological mother too, damn that boy would be going for 2/2 on the mother murders.
There are too many loose-ends to really solidify this as an AU fic that I'd write, but it most definitely is something that I would be interested in outlining and potentially working on in the future. I can just imagine the following:
"Oh why am I doing this? I want to see you suffer, Kaname Date. Awwww, Mr. Date, why can't you understand! Or, should I call you UNCLE? How about Big Brother? hahHAHhhahHAhh, you REALLY didn't know?! You don't even know who you are and now you want to know more about who I AM?! I'm the brand new star of the net world, A-set Tesa Iris the cyclops killer, of course!"
I could go on and on, how she'd talk with punctuated cutesy gestures, mocking the actual Iris, how she'd reference all the previous flashbacks that Date has had, how she'd speak in a (practically) flawless impression of Iris. To play the entire game and to realize at the very end that the person you needed to save is already dead, and in her place is a vicious murderer in a body that you swore to protect, that would've been something alright. If the body swap happened then Date would've been absolutely fucked as Iris afterwards since the livestream would've revealed her as the killer, and he would likely die in his daughter's body in the same prison that had his true body, unable or unwilling to bodyswap with him and "return home" himself.
That route is the absolute worst of the game, and yet sometimes I wish it was even more disgusting.