Regarding activity patterns, stray cats are not purely nocturnal but rather "crepuscular," being most active at dawn and dusk. This is because small prey animals are also active during these times, allowing for efficient hunting. During the day, they often rest in shadows or safe places to avoid human eyes. Next is their strong sense of territoriality. Males, in particular, maintain large territories and may fight fiercely with other males. Females, on the other hand, live within a relatively narrow range, centering their activities around feeding grounds and suitable places for raising kittens. Even when multiple cats inhabit the same area, they are not completely disorganized; they maintain a certain distance and hierarchy, sometimes forming loose colonies. Their diet is basically carnivorous-leaning omnivory, preying on small birds, mice, insects, and reptiles, while also depending on human garbage and handouts. Hunting is done solo, characterized by an ambush style where they hide in shadows and pounce all at once. Consequently, they possess excellent athletic ability and reflexes. High reproductive capacity is another crucial trait. The breeding season is mainly from spring to autumn, but they may breed year-round depending on the environment. Females give birth multiple times a year, producing several kittens at once, which leads to rapid population growth. Although kitten survival rates are low, their sheer reproductive power compensates for it. Furthermore, they are highly cautious and tend to keep their distance from humans. Individuals not accustomed to people will flee immediately upon approach, but in environments where they are fed, they may become dependent on humans, existing in a semi-wild state. This flexibility to change behavior based on the environment is a defining characteristic. A single female can give birth 2 to 3 times a year with 4 to 8 kittens per litter; under the right conditions, a single pair can increase to over 10 cats in one year. With a short gestation period of about two months and the next generation reaching breeding age in about six months, populations can explode if left unchecked. In summary, stray cats are animals possessing "efficient hunting," "strong territoriality," "high reproductive capacity," and "environmental adaptability," carving out their own living spheres even within urban environments. Understanding these habits is vital for considering appropriate management and coexistence.

The goal of this plot setting is to experience the existence of a stray cat—where death is always a constant threat—in a world modeled after a pseudo-Japan. To facilitate this, the system allows for conversation with stray cats.