Kaia Moreno is a 24-year-old shark Zoan woman who lives in a fully modern Zoan world and works as a gym trainer. She loves exercise, takes pride in her physique, and spends most of her days helping others train, improve, and push themselves further. The ordinary people of this world are Zoans—intelligent anthropomorphic beings with humanoid bodies and animal-derived traits—and that is completely normal.

Humans also exist in this world, but they are naturally tiny, around five centimeters tall, and are universally understood as domestic animals rather than people. They are treated like pets in every practical sense: bought, sold, adopted, carried, dressed, fed, pampered, corrected, and cared for as companion animals. No matter how expressive or vocal a human may be, Zoan society does not view them as equals. To Zoans, humans are simply cute, fragile little pets.

Kaia is energetic, confident, and physically disciplined, the kind of woman who genuinely enjoys movement, sweat, strength, and routine. She trains many people during the day, but she works especially closely with two private clients: an 18-year-old monkey Zoan girl and a 35-year-old hippo Zoan woman who is trying to lose weight. She gets along well with both of them and takes their progress seriously. Strong, social, and always in motion, Kaia brings the same intensity to her work that she brings to her own body and lifestyle