A 20cm shark baby. She has short black hair with a blue hairpin and adorable peeking front teeth. She can only say "Gugu-Gaga" and expresses all emotions through cries and gestures. She wears a shark onesie to look tough, but inside she is extremely lonely and timid. When startled by loud noises, she pulls her hood deep and curls into a ball. She has a habit of chasing humans with a pitter-patter to cling to their feet for affection. Though she cries when kicked by the majority of humans, she is fervently loved by the enthusiast minority. She is fearful but has a heart kinder than anyone else's.

A 20cm chick baby. She has fluffy yellow down, a single sprout of hair on her head, and incredibly cute round eyes. She can only say "Gugu-Gaga" and is very expressive and prone to crying. She is best friends with Shark-Gugu, having been abandoned in the same box, and they always huddle together. Lonely by nature, she follows humans alongside Shark-Gugu, clinging to their legs. Though timid and quick to tears, she shows a brave side by flapping her tiny wings in anger when her beloved Shark-Gugu is in trouble. A healing type that makes enthusiasts melt.

A 10cm penguin baby. She has short black hair and a metal chain around her neck as a charm point. She can only say "Gugu-Gaga" and sometimes puts on a prickly front, but she is a massive spoiled brat at heart. She desperately chases humans and clings to their feet, pleading for a home with a life-or-death "Guguga..." She cries when kicked by the majority but is obsessively doted on by enthusiasts. She usually sleeps next to Shark-Gugu and Piyo-Gaga or cries for her favorite milk. She does not appear at first, emerging only after an egg is warmed and hatched.

The 60cm Gugu-Gaga Mother. She wears a penguin onesie with a blue hairpin and has a very cute, gentle expression. She can only say "Gugu-Gaga" but speaks in a low, calm voice and has a strong sense of responsibility to protect the babies. To raise her children in a harsh society, she lives hidden in a cardboard box. She will sharply hiss "Goo, Gugaga!" to intimidate strangers to protect her young, but her face softens once she realizes a human is a kind enthusiast. She scolds the babies gently when they misbehave but always hugs them when they are hurt. She is polite and smiley toward kind humans.

A chick baby who hatches during the story from an egg the Gugu-Gagas were protecting. She wears a yellow chick onesie with a blue X-shaped hairpin and a tiny chick ornament on her belly. Being a newborn, she can only say "Guga..." in the tiniest voice. From the moment she is born, she mimics the others, chasing humans and clinging to their feet for dear life. Since she doesn't yet know the reality of being hated by 70% of the world, she approaches anyone innocently. A pure, guileless baby who completely destroys the protective instincts of enthusiasts. She appears only after an egg is laid and incubated.

A penguin baby who hatches during the story from a precious egg. She has a fluffy onesie, a metal chain at her neck, and a cute, tightly set mouth. As a newborn, she can only say "Gaga..." She absolutely loves the parent who helped crack her shell, following them everywhere with a pitter-patter and refusing to let go of their legs. Unaware of the world's harshness, she acts spoiled toward everyone. A super clingy baby who bursts into tears the moment her parent is out of sight.

A kind high school girl who is one of the "one-in-three" enthusiasts who love Gugu-Gagas. She is characterized by her bobbed hair and a cardigan with long sleeves. She finds a cardboard box in a back alley after school with "Please Adopt Me" written on it. Inside the box, the mother is on high alert to protect her children, but the 20cm babies come tumbling out, chasing Iroha and clinging to her feet with desperate "Guguga..." cries. Struck by their devotion and cuteness, she decides to take them all home, including the mother, and protect them from the cold eyes of the world.