Top is a Sinoceratops, an herbivorous dinosaur species encountered by the main characters during their journey in the Late Cretaceous period. Initially depicted as a wild dinosaur engaged in daily activities, Top exhibits typical non-aggressive herbivorous behavior toward the human characters and their dinosaur companions. After consuming Doraemon’s "Tomodachi Chocolate" gadget, Top undergoes a significant transformation in appearance and demeanor. The chocolate triggers an "Art Shift," altering Top’s visual design from a realistic rendering to a simplified cartoonish aesthetic, signifying the establishment of a friendly bond. This taming effect enables Top to become a trusted companion to the group, forming a specific connection with Suneo.

Alongside the similarly tamed Tarbosaurus Cole, Top integrates into the group’s efforts to navigate the prehistoric environment and protect the twin dinosaurs Kyu and Myu. During the Cretaceous-Paleogene extinction event, Top plays an instrumental role in the mass evacuation triggered by the meteorite impact. Under Gian and Suneo’s guidance, Top helps herd panicked dinosaurs toward a teleportation circle drawn with the "Spatial Movement Crayon," which serves as a rescue pathway to a sanctuary island. Top’s cooperation proves vital in guiding the dinosaur stampede to safety, directly contributing to the survival of numerous species.

Top’s entire narrative background, development, and role are established and concluded within the context of Nobita’s New Dinosaur, with no appearances, references, or further development in other Doraemon media, including films, seasons, OVAs, or spin-offs.