Murashigure (a Touhou LW original) refers to showers that stop and start over the course of the day. This is the temperament of the Kosuzu Motoori, who wanders the gray area between human and youkai. Kosuzu is strong against Water Phase and Moon Essence, the essential elements of youkai, but is weak to Sun Essence, since sunlight can end the Night Parade.

The ability of Kosuzu Motoori from the world with an ultra-forbidden scroll (a Touhou LW original). This ability doesn't seem any different from the Kosuzu of our world's ability. The 16.3rd Prolonged Incident. Kosuzu left Suzunaan, taking several demon books, including the Privately Published Night Parade Scroll's final chapter addendum, and nobody knows where she went. Before she left, Akyuu, her best friend, told her that she must choose the truth that she thinks is best... so it seems likely that she left in search of that truth. But which truth did she choose in the end? The records do not provide a clear answer, and neither can Kosuzu because she forgot everything once things returned to normal. When Akyuu and Reimu asked Aya about what happened to Kosuzu, Aya speculated that she may have been spirited away. In other words, kidnapped and sent to the outside world. If this is true, Kosuzu's first stop after leaving Suzunaan was probably to meet with Yukari Yakumo. Then, the incident would proceed and eventually be resolved according to Yukari's plan. However, for some reason, it did not get resolved in this world. It became prolonged. Kosuzu probably brought the demon books with her because Yukari had convinced her that everyone was trying to take them from her. Assuming Yukari brought Kosuzu to the outside world and showed her what it was like, this experience probably led Kosuzu to make the following conclusions about Gensokyo. - The ordinary humans of the village are being kept in the dark and exploited. - Powerful humans, like Reimu and Marisa, are plotting to rule over Gensokyo just like the youkai. - If Kosuzu uses the power of her Night Parade Scroll, she can correct the imbalance of power in Gensokyo. Reimu and the others assumed that Kosuzu was possessed by the power of the evil black dragon and that the tsukumogami of the Night Parade Scroll were trying to eat her. However, Kosuzu might have thought that the reason why the humans of the village couldn't live freely like those in the outside world was because the powerful humans, like Reimu, weren't fulfilling their duties. So, perhaps Kosuzu was acting under her own will and genuinely wanted to teach Reimu and the others a lesson to correct the power imbalance in Gensokyo. Assuming Kosuzu was trying to do the right thing as a youkai-exterminator, then Yukari should have been able to follow her plan and transform her into a being, similar to Reimu, that straddles the boundary between human and youkai. Yukari starts incidents, but she also helps resolve them, like with the Eternal Night Incident. Everything would sort itself out as long as Reimu fought Kosuzu, and Reimu would have every reason to fight because she would still be thinking about what happened with the fortune teller. So, where did Yukari's plan go wrong...?