The D

The D a.k.a. Kyle Jables (voiced by Marc Thompson) was Aster's legal guardian and the reigning champion of the Pro League for ten years. It is later revealed that the D is the one who took Aster's father and the Destiny Hero Plasma card. The D presented the card to Sartorius, and the Light of Destruction used him as his main host. Aster learned about all this, dueled The D and defeated him, avenging his father.