Pucca was an adopted superhuman
There isn't any mention of Uncles Dumpling, Ho, and Linguini having any siblings, and Pucca isn't exactly a normal human being since she can run pretty fast, mow through enemies threatening Garu with ease, and can take boulders to the head without any ill effects.
Pucca is actually a god in human form, or the god's Human Can
It would explain why she has no direct family, where she gets most of her physical abilities, how she suddenly gets super powers whenever the plot demands so, and why everyone but her supposed "enemies" seem to just naturally adore her. She's a God-Mode Sue who is actually a god!
The show frequently claims that Garu is some sort of Chosen One
, by this logic, Pucca is an avatar of a goddess sent to protect him.