Peko is a light yellow stuffed kitten featuring light orange ears, arms, and legs, creating a pastel Siamese cat-like look. His design showcases a long tail, rounded ear tips, pink star-shaped paw pads, and a yellow star in his left ear. He sports a yellow bandana dotted with orange polka dots and carries a light blue bag decorated with a dark blue star.

His cheerful personality revolves around eating and comedy. The name Peko likely stems from the Japanese word "pekopeko," meaning "very hungry," reflecting his deep love for food. He consistently speaks in Kansai dialect and delights in making others laugh through jokes and comedic antics. His origin involves falling from the sky before being found by his human partner, Maira Tsukishima, mirroring other stuffed kittens' beginnings.

As Maira's partner, they form the comedy duo "Dasshi♡Fun'nyuu" ("skim milk powder"), their shared passion for comedy driving their interactions and collaborative humorous performances. Peko's abilities include entering human dreams with other stuffed kittens to purify nightmare-causing "black abysses," though his specific powers remain less defined than characters like Suu. He belongs to a group including Mew, Suu, and others, sharing their goal of maintaining positive dreams, positioning him as a rival to the mischief-making Yuni.

His relationships extend beyond Maira to interactions with fellow stuffed kittens. Notably, upon first meeting Rei, Peko displays strong admiration, reacting with visible excitement and flustered behavior. Throughout the series, his role remains consistent as a supportive and humorous figure, participating in group missions to protect dream worlds while maintaining his comedic partnership with Maira. No significant character evolution or additional background details beyond these elements are documented across official media.