Rin woke up with a start, screaming. Immediately, she noticed two things:
1. Her bondage. Rin’s ankle’s were bound to the floor, her neck collared and bound to a metal pole, and her hands painfully died behind her back,
2. She couldn’t channel magic.

This was bad. A palpable sense of dread washed over the young magus. What had she been doing before waking up? What happened? Every time the mage tried to remember, she was met with an awful headache instead. She decided to collect her bearings and scope out the situation.

First, she needed to figure out where she was. The room seemed like some sort of weird basement dungeon. The walls and floor were made of stone and the only exit seemed to be the one door at the top of the stair case. A relatively innocuous looking room, but something about it felt… familiar. Another splitting headache.

“Hehehe, looking quite delectable there Nee-san.” Rin froze. That was… Sakura’s voice. Then, her memories came flooding back.

Rin had been fighting Sakura with her jeweled sword. She was close to defeating her when suddenly, Saber had reappeared. Shiroi had failed. Unfortunately, the young magus, jeweled sword or not, was no match for these two opponents. As she was being absorbed by Sakura, she remembered these words “Don’t worry Nee-san, I won’t kill you. You’ll suffer inside of me. Forever.”

Rin broke out into a cold sweat. The reason this room seemed so familiar was because it was. This was the room where she had seen all those lust worms. This was the Matou estate. “Sakura, please let me out. Don’t do this. Please.” Rin begged. All she was met with was a snicker. “Perhaps once you experience everything i’ve gone through, we can talk Nee-san. Until then, enjoy their company.”

With that, the room filled with the chittering of worms.

Lust worms - A species of magical worms utilized by the Matou family. The worms will transform when attacking a woman, so that they are only able to violate her nerves. They will spread their tentacles all over her body and devour her spirit. The lust worms will wet the woman's skin with their mucus, excite and destroy her central nerves of pleasure, and satisfy their hunger. It must be their instincts, as the worms seem to love the woman's womb. They do not eat female flesh, but seek the organs within them. They give the woman huge enough orgasms to fry her brain, and they go into her body to devour her placenta. Unwilling to eat human flesh, the worms have only one way to get what they desire. As a result, the woman's mind and body are completely violated and destroyed.

This was what Rin was facing. The seemingly cold mage couldn't help but cry as she saw the worms approaching her. She knew there was no way out. The only way she'd ever escape is if Sakura granted her the mercy of death. Rin knew in her heart of hearts that her sister never would.

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Commission by kahncom