Phantasy Star Online Episode III: C.A.R.D. Revolution

A strangely powerful Photon-like substance found on Planet Ragol has spurred a raging battle between the Hunters and a rebel team called the Arkz. The prized matter known as “The Germ” has unique replicating powers and can be sealed in small playing-card-sized packets. Warriors carrying a deck of the sought-after cards can then bring unprecedented amounts of destructive weapons and creatures into battle. Fight with the Hero Hunters or on the rebels’ Dark Side and stack your decks accordingly. You’ll compose several powerful decks from nearly 500 cards featuring fighting moves, weapons, and PSO creatures.

Source: TheGamesDB