Magia Record Story The Ribbon at the Brink Where the Waves Break
The following is a summary posted on 4chan's /pmmm/ general by Summary Anon.
Two girls, Kei and Yumi enjoy expressing their love via S&M, leaving scars on their necks. Eventually, they choose to commit suicide since they felt that they will eventually be torn apart by people, their opinions, and time. They swear to kill each other for every reincarnation as long as they meet each other.
Kei died while Yume lived. Kei's spirit was caught by the Witch by the seaside and gained enough consciousness to look for Yume, causing a haunting.
Homura got haunted since she read Yume's diary. The Holy Quintet are targeted since they reek of blood and curses, making Kei think they killed Yume.
Kei possesses Madoka and tries to kill Homura with Madoka's body. Ren comes to her aid and tells Homura that what is possessing Madoka is no witch nor rumor.
They beat the witch by the seaside, and Kei forces Homura to promise to kill off Yume before she loses herself no matter what world or time Homura jumps to.
The conclusion revealed that Yume contracted and became a Puella Magi. Some believe that in this loop, Yume had already become a witch and was hunted, which is why Kei believed that the Holy Quintet were the witch hunters as well as her killer, causing her to tell Homura to kill Yume next time before she loses herself so she can reunite with her.
Homura was the targeted body, but Kuro warned Homura in time by waking her up despite already having been a hunted witch.
Ren can see ghosts, souls and spirits.