Danganronpa v3 au with a twist, literally thought about this.

Chapter 1:

First victim: Tenko chabashira, was hit with a metal ball hard on her skull like rantaro's death, her body was found inside the library.

Blackened: Angie Yonaga, she thought it would be a good sacrifice to atua, she was brutally murdered to death by all of the followers, who are shadow created by monokuma.

Chapter 2:

Second victim and blackened: Ryoma Hoshi, committed s*icide due to his depression, hanged himself inside his room with a note.

Punished: Gontas AI avatar, like Alter Ego in danganronpa 1.

Chapter 3:

Victims: Miu Iruma and Kimuri Tojo, both were slaughtered with a katana by Kiyo.

Blackened: Still Korekiyo, nothing changes there.

Chapter 4:

Fifth victim: Himiko Yumeno, found bruised and beaten up with bug blood on her body in her room while doing virtual reality.

Blackened: Still poor Gonta Gokuharra who's feelings was hurt by miu, and death threats by monokuma which the notes were on his door step, which let him turn to insanity.

Chapter 5:

Sixth victim: Kaito momota, was stabbed ten times with a kitchen knife on his stomach, his body was found in maki's lab.

Blackened: Maki harukawa, she did do it due to her being an assassin because Kaito was one of her victims she had to kill, her execution was like Peko's in danganronpa 2 but she wasn't controlled, which when Kokichi tried to save her, which left him have a scar on his stomach.

Chapter 6;

The punished and the real mastermind: Still Tsumuigi shirogane.

Survivors: Kaede Akamatsu, Rantaro Anami, Shuichi Saihara, K1-B0/Kiibo, and Kokichi Ouma.

Yeah, all of my favorite characters survive in this AU, yey!

Right, the question was, how did Tsumugi die and kiibo didn't, well, Kaede let hope win like Makoto did in danganronpa 1.