In Kochi, people have ruled the land through castle towns beginning in the Middle Ages. I propose an ecological network as the future of the city, which will be intertwined with the existing urban axis, attracting non-human creatures to the city, with a view to their symbiosis. Based on the "ecological map" created from the survey, we attempted to create a design that is appropriate to each location. As a large ecotone of continuous mountain, river, and urban ecosystems, the boundary between the city and nature will be seamlessly connected through the intersection of ecosystems, creating a new urban space in Kochi by making spaces designed for living creatures a part of people's living space.