Aiko

8 kids in Japan were picked at random and were put in a science experiment - see what happens when they put a child into a computer. It worked, but the energy used resulted in them getting trapped online, separated from their parents, for 3 years, until Normal and co. found them (except one, who was stuck for another 3 years before meeting the group). Since then, they've stuck with the group through thick and thin.

Also, I'm not gonna write their movesets, each person here was based on one of the original 7 (later 8) Digimon, so whatever move that Digimon can learn, they can use it here.