Battle Spirits: Shounen Gekiha Dan

Dan Bashin, known as the Clash King, is a skilled player of the card game Battle Spirits. He's transported to Grand Rolo, a fantastical land where disputes are settled through card duels, by a mysterious girl with green hair. In Grand Rolo, Dan becomes entangled in a conflict between the kingdom's imperial army and its oppressed subjects. He discovers he's a prophesied warrior, a "bearer of cores' light," destined to save the land from its tyrannical ruler.