Willis Fast Facts
Season: Digimon Movie (part 3/S2)
Digimon: Terriermon (and Kokomon/Lopmon)
Other: The only Digidestined to have more than one Digimon partner. He's American, too.
Willis is an American kid who turns up in Digimon: The Movie. We learn that he grew up a bit of a loner, with no friends. From the dates we know, he was probably about 4 or 5 when he got his Digimon partners (twins).
Willis is really smart. In part 2 of the movie, Izzy reveals that he's only an elementary (=primary) school kid, but he's already taking classes at college (=university).
In Digimon: The Movie, Willis was trying to create another Digimon to play with when it was hit by a virus and started digivolving evilly. At the end of the second section of the movie, Kokomon was swept away by the virus and turned into a monster. T.K. and Kari met him in New York when Kokomon had tracked him down and was attacking him. At the end of Digimon: The Movie, Kokomon was purged of the virus and got reconfigured. ("Digimon never really die, they just get reconfigured.")
In Season 2, Willis works with his friend Izzy to analyze the D-3 Digivices.
If you're wondering why Willis is in the S2 section, and not in the International DD section, it's because the S2 fits him better - he actually interacts more with the S2 kids.