If you haven't already, you can start reading from Part 1 here.
The stories and images here belong to Compile Heart, and you can view the original on their website here: https://www.compileheart.com/mary-skelter/tuu/special/ss/index6.php
Her name was Kaguya. It seems that she had lived in a small village and fought off the Marchen that occasionally attacked it.
But, in the eyes of her fellow villagers, Kaguya's power wasn't that different from the Marchen. Even Kaguya's adopted parents grew to detest her powers and presence, and they eventually found out about and contacted Dawn, asking them to come take Kaguya away from them.
When Kaguya first came to Dawn, she had her abilities measured and delivered some good lab initial test results, but after that, she became a shut-in, always locked away in her room.
The other Blood Maidens were worried about her and invited her to come play with them often, but Kaguya's psyche was severely damaged. Professor and Miko told the other Blood Maidens to give Kaguya some time to herself too, so the days went by with them only occasionally seeing her in passing.
And then, one day - Chiaki had grown up more, and solidified his position as 'Hitsuka' in the Order of the Sun, and in a rare move, he made contact with the Blood Maidens, asking to see them.
Three years earlier, Chiaki had started investigating the mystery behind his sister and the blood sample that Tsuu had told him about, and had been continuing that investigation to this day. Now with trustworthy subordinates, he could conduct far more thorough investigations than he had been able to do when he was younger.
He didn't tell anyone, but he was coming close to discovering an important truth. In order to confirm it, he needed to ask the Blood Maidens about some things directly.
The things he asked them weren't difficult to answer: "What is your oldest memory?" "When did you become aware of your own name?" "What kind of experiments are you undergoing at Dawn?", things like that. If they couldn't answer, he didn't get upset.
The last person he questioned was Cinderella. The questioning order was random to Chiaki and didn't mean anything, but the negative-thinking Cinderella wondered why she was last, had she done something bad?
She was scared but still answered Chiaki's questions. After finishing his last question, Chiaki seemed lost in thought, stroking his jaw, and muttered something like he was thinking out loud to himself:
"Why are seven Blood Maidens needed...?"
Hearing that, Cinderella's heart pounded suddenly.
Seven Blood Maidens are needed. That was something Professor had said from a while back. That's why Professor was so happy when the three sisters joined and their squad reached seven members.
But, right now, there were eight Blood Maidens.
After parting with Chiaki and returning to her own room, Cinderella's heart continued to pound. In the order of her room, she held her knees close and quivered softly.
(Seven Blood Maidens are necessary...but, since Kaguya arrived, there are eight of us. Basically, that means one of us is unneeded? If so, who? Kaguya left good results in her initial lab tests...Right now, the most worthless one is...no, this can't be...something, there must be something I can be useful for...)
Even though she hadn't come into contact with Marchen blood, Cinderella's eyes flashed pink for a moment.
"...would be a good idea to pick one Blood Maiden, and investigate the physical and mental effects of 'impurities' on her in our experiments."
"But that would be..."
From their experiments, they had confirmed that Blood Maidens' blood could build up 'impurities' from taking physical or mental damage. Until now, in order to safeguard them, when that impurity reached a certain level they would stop the tests. Now though, Professor thought that a test of what happens when those levels are exceeded was necessary.
"This is a test we have to perform eventually. I can't help but suspect that there's something beyond the Massacre Mode they go into when impurities build up to a certain level. Thinking about the development of the Blood Maidens, in the worst case scenario, that 'something' could bring about a calamity so large that it plunges all our hopes into darkness.
"...Even Red Riding Hood is still only 15. If you do such dangerous experiments, you could really end up breaking them."
"Yes, that danger does exist. But, remember - the number of Blood Maidens we need is seven. Which means...you know."
"I can't go along with this line of reasoning!"
Professor tried to calm down a furious Miko. Taking a deep breath, Miko changed the subject.
"More importantly, I'm concerned with the Order of the Sun's recent moves."
"About Hitsuka, yes?"
"Yes. It seems he's using his worshipers for some purpose. He questioned our Blood Maidens, too. There are rumors that the Order is starting its own private fighting force. Shouldn't we be focusing our investigations on them?"
"Hmm...we let them act freely until now, but that boy is gathering more and more power. This might become troublesome..."
Professor stroked his own hair in thought.
Then, just outside the doorway, a faint clattering sound rang out.
Miko walked over to the door and slowly opened it, but nobody was there.
"Who was it?"
"...there's nobody here."
Professor stroked his har in thought again.
The next day, Cinderella had disappeared from Dawn.
Dawn's personnel searched furiously for her, but couldn't find a trace of her whereabouts.
Professor said that in the worst case, she could have wandered into a different area by herself and been killed by Marchen. Nobody wanted to believe that at first, but after a full month of not being able to find her, the Blood Maidens were filled with a sense of despair.
"Did Cinderella really go to a different area by herself...?" Tsuu wondered in a pained sounding voice.
"But, our people did search in different areas." Mermaid raised the point in disagreement.
"They just checked the entrances to them, where things are the least dangerous. They couldn't have checked too far inside." Red Riding Hood said grimly. To her, Cinderella was like her closest younger sister.
"If she did, why did she go somewhere like that alone? We're always told to stay away from those places."
Thumbelina had been distancing herself from the other Blood Maidens besides her sisters as she felt the relationship between Dawn and the Order of the Sun souring recently, but she wasn't distant enough not to also feel worried in a time like this.
"For a long time...Cinderella has been worried about not performing well in her lab tests, so..."
Sleeping Beauty muttered a couple notes of agreement to Snow White's assessment, frowning in concern.
Professor had told the Blood Maidens to stay out of this and leave the search to the adults, but they were at about their limits.
"We should help search too -" Tsuu started to say, but was cut off by a loud commotion coming from outside. They couldn't hear it precisely from inside the building, but it clearly wasn't a pleasant atmosphere out there.
"What's going on...?"
"Let's go see!"
Red Riding Hood set off running and the other girls followed after her.
As they stepped outside, they saw a huge mass of people barging into Dawn's vicinity shouting something. Looking closer, they were adherents from the Order of the Sun.
The confused members of Dawn were being hurled verbal abuse by the Order of the Sun believers, and that just increased in intensity as the girls stepped outside.
"It's them! It was one of their friends who killed Hitsuka!"
Thumbelina's expression froze.
"That's right! I saw it too! A blue haired kid wearing the same clothes as them! She killed Hitsuka right in front of us!"
The furious gaze of the adults at the Blood Maidens was something they were too bewildered to respond to.
But, Thumbelina alone began to slowly approach one of the adherents and called out to them.
"Hitsuka...you mean...Chi? Chi was killed? What are you saying?"
It seems this believer was one who remembered Thumbelina from when she stayed at the church, and he put his hands on her shoulders and continued loudly -
"Thumbelina, it's you! You three, come back to us, quickly! It's like we thought, we can't trust Dawn!"
"I'm telling you to explain what happened to me!"
Thumbelina raised her voice even louder in response, and cowed by that intensity, the believer lowered his voice a bit and began to explain.
"Hitsuka started making a reconnaissance team to explore other areas a while back. I was part of it. Yesterday, when we started our scouting into one of the areas, a girl wearing the same clothes as you all showed up out of nowhere, killed Hitsuka, and then disappeared further inside the area..."
The Blood Maidens were speechless.
After a long silence, of course it was Thumbelina who finally broke the silence.
"That's right...long blue hair that went down to her waist."
A Blood Maiden outfit, and waist-length blue hair.
Among the Blood Maidens, there was only one person that could be.
"...Snow, Sleepy. We're going back."
Suddenly, Thumbelina grabbed hold of her sisters' hands, and walked forward quickly with them.
"But...Thumbelina, big sis...!"
The two of them showed a token amount of resistance, but in the end they allowed themselves to be pulled forward by their older sister.
No, we can't let them leave like this, Tsuu thought as she ran towards them and reached out her hand behind them.
"Shut up! Don't follow us!"
Thumbelina's grief-ridden scream stopped Tsuu's hand in its tracks.
"...I'm going to find out if what they said is true. So, for now..."
she couldn't meet Tsuu's gaze directly, even until the end.
"...For now, don't come after us!"
Her words were squeezed out, soaked with pain and despair.
Like that, the three sisters left Dawn.
But, nobody came back.
The truth of what had happened left unknown, Cinderella left missing, the only thing they confirmed was finding Chiaki's corpse. The Blood Maidens were banned from even attending the solemn funeral that the Order of the Sun held for him.
Several months later, the three sisters had become the new 'Hitsukas' of the Order of the Sun. Miko went and checked on them and confirmed that they weren't wearing their Blood Maiden outfits anymore either, but the garbs of the church.
The Blood Maiden Squad had suddenly been reduced to only four in number. Accordingly, the lab experiments began to become more cautious.
A seeming change of heart caused Kaguya to suddenly stop staying cooped up in her room, and enthusiastically participate in the lab experiments. It was something they should have been happy about, but it seemed like Kaguya was being haunted by something they couldn't quite understand, and that unease spread to the others watching her sudden change as well.
Red Riding Hood believed Cinderella was innocent, that there must have been some sort of misunderstanding. Professor also tried to persuade people in hopes that the three sisters would some day come back to them.
"Why did things end up like this?", Tsuu kept wondering.
Finally, five years later, a new Blood Maiden was found.
Nobody had any way of knowing at the time that this was just the opening act for a story of far greater despair.
That's it, folks, the end! Or the beginning, if you prefer. I hope you've enjoyed reading this, and that it enhances your enjoyment of Mary Skelter 2. Personally I felt like it helped me understand and sympathize with the new motivations of each character when I read this before playing the JP version of the game; although they do go over the events of the prologue, it's not nearly as in-depth as these short stories are.
Check out the OP for Mary Skelter 2 and see if it vibes differently with you after reading this - I know for me at least, it made the portrayal of Thumbelina, Snow White, and Sleeping Beauty in it a lot more understandable.