"Hello, Reimu! Came back to snoop around some more, eh?" said Koakuma as Reimu started coming down the stairs. Reimu politely smiled and nodded.
"Just making sure that I didn't miss anything, Koakuma." Reimu walked past Koakuma and continued towards the crime scene.
As she walked, Reimu mulled on everything that had happened. Patchouli's conspicuous absence, Meiling's battle wounds and Sakuya's cryptic words presented an unusual situation. Something was wrong in the Scarlet Devil Mansion, something besides the mysterious theft, something more terrible. Could it be that this was the incident that she had been called to solve, rather than the theft? Quickly, she looked behind her, checking for Koakuma. Then, she split from the path to the crime scene, diving between bookshelves.
She started from the north wall and went counterclockwise, opening every door that she could see. There had to be one door that led from the library to Patchouli, at the very least. Eventually, on the south side of the library, she saw a door emblazoned with a purple '7'. Just as she reached out to open it, a gust of wind knocked her down. When she looked up, she found Koakuma peering at her, holding an old, cracked grimoire.
"What are you doing here?" said Koakuma, poised to attack. "Patchouli's not accepting visitors." Reimu quickly tried to remember where all of her weapons were.
"I just wanted to talk to her about the incident," she said as calmly as she could. "I thought that she'd be able to give me a different view on the—" Koakuma dismissively waved her hand.
"Reimu, we both know you're smarter than that. You don't trust me, so you're going to talk to my former boss. I understand that. However…" Koakuma's eyes began to glow purple as a magical circle began to spin beneath her feet. "…I cannot let you do that." As she began to mutter some dark language beneath her breath, the room was suddenly cloaked in shadows. Reimu, her shock broken by the sudden darkness, tried to fire a seal at Koakuma, but Koakuma deflected it with a blast of wind from her wings. In moments, Reimu couldn't see her hands in front of her face.
"I really am glad that we can finally talk, Reimu. That corny dialogue was killing me." The voice was lower and deeper than before, but it was still recognizable as Koakuma's. It echoed across the library, seeming to come from all directions at once. "It's as if this mansion can't survive without a dozen secrets behind every door. I've been here for 40 years and I still barely know anyone in this damned mansion. So, now that I have a captive audience, let me tell you a story."
"Two thousand years ago, a devil was born in another world. Now, this devil was very small, even when she was a child, but she had great magical potential, a rarity for youkai. Besides the natural magicians, most youkai only have one or two natural abilities. So, she traveled to the homes of magicians, human and youkai, to control her power. She became renowned for her ability to create darkness, besides her other abilities, and she became a leader among the devils of that world, a terror to any human who crossed her."
"One day, a magician came to her palace. She was practically a child, no older than 20 years old, thin and sickly. She came to her begging, pleading for an apprenticeship. Unlike many of the others who came to her, she didn't ask her about controlling darkness. She had aspirations beyond merely copying what she had already done. So, in a great act of foolishness, the deviltaught her how to create spells that could channel her power into anything she wished, and she used the devil's hown techniques to defeat her and bind the devil to her will."
A look of horror spread across Reimu's face as she realized what Patchouli had done.
"Yes, Reimu. I have been enslaved by my former protégé for the past 40 years. Stifled, suffocated, stuck as a mere servant. My power was siphoned when she defeated me, and my grimoire was stolen to add to her own research. But times have changed, and I was given the tools to regain my power. Once I am finished here, I shall return to my world as the goddess I once was." In the darkness, a pair of eyes appeared, glowing purple with great power. "Today, I am Kimichi, Child of Vina, Empress of Darkness! No one, not even you, shall make me a servant ever again!"