My guess was that the crazy marisa remembering that it suppose to had a beloved reimu but had a sudden realization that that reimu is nowhere to be seen and after seeing the memento from the reimu it had, being a sick crazy fuck it was, thought it was the reimu and fucking it Or anyone had other opinion or willing to translate it? ^^
1. A stray Reimu came to hide from the rain, from face and attitude in the pics, maybe an average (not Deibu). Marisa then fall in love with her and asked her owner to let them be together. <== 11th panel - Marisa later thought she saved Reimu from the trash. <== 8th panel's narration
2. Mister don't like dirty stray. Marisa tried appealing. 3. Mister then asked Marisa to try pretending she's a stray. Marisa don't want to. She believed strays can be good (and maybe romanticized stray life). But he hit her and forced her to do it. The mister also abused her like stray and forced her to admit stray is dirty. <== from the last black panel
4. After finishing the play, Marisa seems to go insane. Later when the owner took her badge, she starts asking to let her pretend she's a "pet yukkuri" longer (actually she's a pet pretending as stray). <=== 4th panel
5. Marisa is abandoned and got picked up by another person (a white dressed Miss?) who took care and heal her wounds. - Marisa thought she's king of the forest and demanded to be returned outside so she can help her clan to prepare for winter <== 5th and 6th panel.
6. Marisa thought the Reimu doll is her Reimu who came out of worry because Marisa never come back home.
7. Marisa heard that her previous owner is arrested (no info if it's yukkuri related or not). Marisa think that must be wrong, because there's no way the Mister who gave her gold badge got arrested. <== 8th panel
8. But Marisa realized she doesn't have the badge. Without the proof as a pet, she can't go outside <== 9th panel. Previously she still think she's a stray, or at least "a stray with gold badge"
9. Marisa starts remembering again what happened. <== panel 11-13
10. Marisa found one of Reimu's braid in her hat and starts thinking that's Reimu.
Last panel hinted that the stray Reimu is still alive, with a koyukkuri that might be Marisa's child waiting for Marisa to finish "learning about strays". Maybe the Mister only ripped off one of Reimu's braid and let them go.
Some part of the story (the insane-Marisa's side) is confusing and inconsistent. Maybe there's mistranslation/interpretation too. Any correction ?
Pet yukkuri Marisa fall in love with a stray Reimu who came for shelter from the rain.
Mister doesn't like the dirty strays.
To teach Marisa about the repulsiveness of strays, Mister ask Marisa to play pretend as a stray.
Marisa protested on the Mister's bad intentioned pretending play. That angered the Mister and he took away Marisa's badge.
Even though she's a pet, Marisa is tortured like a stray. This has broken her mind.
The abandoned Marisa is then taken in by another home. All her wound are healed, but her broken heart can never heal. Marisa is suffering in state of between a stray and pet.
Through a doll that looks like Reimu, slowly Marisa regained her heart. But one day, she heard the facts of her previous owner. Marisa went to Mister's place, to return to the Reimu she loved. But don't know since when, she already lost the gold badge, her proof as a pet. It all starts coming back to her.
When taking off her hat, a red thing falls down. The Reimu Marisa always want to meet with is always here.
Once again Marisa is broken and she will never come back. But she's living happily with the Reimu she loved the most in this white room.
There is a fatherless family of stray. What kind of suffering has the mother Reimu faced ? One side of her braid is torn off, but she keep on waiting for her partner with her child, always smiling.