Guilmon (to Dukemon), Terriermon (to Saint Galgomon), Renamon (to Sakuyamon), Agumon (to WarGreymon), and Gabumon (to MetalGarurumon).
Damaging opponents or taking hits fills an evolution meter. Once full, pressing the R1 button allows Rookie Digimon to "Digivolve" into their more powerful Ultimate/Mega forms for a limited time. Digimon Tamers Battle Evolution
Hidden characters like Black WarGreymon , Impmon (to Beelzebumon Blast Mode), and Omegamon can be earned by completing specific challenges in Story Mode. Guilmon (to Dukemon)
Each character has a visible health meter that depletes upon taking damage. Terriermon (to Saint Galgomon)