He is friendly and brave.
Taichi gains a Digivice and Koromon evolves into Agumon. After Koshiro informs him that a horde of enemy Digimon (Argomon In-Training) are responsible for the turmoil in the city, and he fights with Agumon to stop them and rescue his family. Just as they are about the defeat all the Argomon, the last one evolves to Rookie and then Champion but both Taichi and Agumon refuse to give in, which triggers Agumon's evolution into Greymon.
When Agumon and Taichi reunited at the Digital World, across Sora Takenouchi, who was also sent there. Agumon and others meet Biyomon running from a hostile Snimon. The group escapes their pursuer by jumping on a river and once at safety, they make a raft so they can continue their journey by navigating on it. While traveling by the river, the four are ambushed by a Coelamon and the Snimon, and while Agumon evolves into Greymon in the order to fight Coelamon. Agumon and the others continue their journey by flying on Birdramon until they reach some abandoned ruins at their destination.
When Agumon and the others are greeted by the spirit of Valdurmon who tells them the story of an old war between the Digimon of light and darkness that the light side won after many sacrifices. Valdurmon also reveals that the forces of darkness are rising again. Taichi and the other children were chosen to stop them, not only to save the Digital World, but the Human World as well, given that both are connected by the network, and instructs them to look for the Holy Digimon at the Cloud Continent. Their conversation is interrupted when an army of Dokugumon led by Ogremon attacks them.