[Card + Battle + Game]
Broken world, graveyard of the world
There are special card rules here. Becoming a card user and conquering the fragmented world are the characteristics of this world.
Robbo came to this world and became a card user. He awakened the system and could replace and upgrade original cards into special sequence cards.
How much energy can he exert in this world?
PS: I haven't saved the manuscript, so I write whatever comes to my mind.
