Piro

Piro (ピロ) is a stray Siamese cat that Nayuki finds and adores, despite her allergies. Later in the story, she becomes attached to Makoto who brings her home, where she is adopted by the Minase Household.

Plot
Piro's full name is "Pirozhki", Russian for "Fried Pork Bun". Yuichi jokingly came up with this name when Makoto shot down the name "Nikuman" (肉まん), as she didn't want her to be named after food. Yuichi then convinced Makoto that it was a made up word, earning her the name.

Piro disappears near the end of Makoto's arc, causing her to leave the house and search frantically for the cat - becoming sick in the process. Sadly, she fails to find her. When Makoto disappears, she is shown lying under a tree, where Piro comes and rubs her arm.

Shortly after that, she returns to the Minase Residence where she is shown to continue staying after Makoto's disappearance.