Welcome to Battle Spirits Saga, the trading card game where cards and cores create an exciting world filled with countless strategies. Long ago, the realms were disparate lands in constant conflict. Then, 250 years ago, a hero called Kei appeared, ending the wars and unifying the realms into a single, peaceful empire under his rule. However, as many histories have proven, peace never lasts. Two and a half centuries later, law and order has grown lax, government corruption has spread, and the empire's authority has begun to wane, threatening an end to the era.