If the motives are the same in 2X2 it would be so interesting to see how Fuyuhiko reacts to Natsumi's death again, assuming he's still alive at that point (I feel like he would be.)
Maybe he actually DOESN'T kill Mahiru, but Peko misunderstands something, moves to kill, and Fuyuhiko is forced to kill Mahiru to prevent Peko from becoming a murderer.
Or Mahiru doesn't even meet up with him in the first place, the letter to her is intercepted and SOMEONE ELSE comes to kill Fuyuhiko instead, knowing he's expecting Mahiru. Even better if Peko comes in and sees him dead before the others. Even better if she SEES IT HAPPEN SOMEHOW and doesn't save him in time, though I doubt that would work in canon because she's like... the ultimate swordswoman. This theory assumes that chapter 2 of SDR2X2 plays the same as SDR2, but differently at the end.
If he IS a killer, I feel strongly that Peko would try act suspicious to shift blame on to her, unsuccessfully.
Like how Fuyuhiko was going ALL OUT to defend her, she'd do the same.
BONUS POINTS IF PEKO INTERFERES IN FUYUHIKO'S EXECUTION.
Bonus Bonus points if Fuyuhiko sacrifices himself to save her in it or something. Or if she gets hurt during it, and Fuyuhiko lowers his guard to help her, causing him to die.
Very Kuzupeko angst pilled.
