Changes

Each season of the series has a primary antagonist. The first season has [[Kagemaru]] (Duel Academy's Chairman and leader of the [[Shadow Riders]], who wants to take the [[Sacred Beasts]] for himself). The second season has [[Sartorius]] (founder and leader of the [[Society of Light]], an enigmatic fortune-teller taken over by an [[The Light of Destruction|alien force]] who uses his influence to bring people to his side). The third season has [[Yubel (character)|Yubel]] creator of the [[Martin Empire]] and the [[Survival Duels]], an evil, deranged, psychotic duel spirit that possesses and manipulates people to rule over all dimensions with [[Jaden Yuki|Jaden]] by her side. The fourth season has [[Nightshroud]] (a former Shadow Rider that is revealed to be the fate of mankind itself, orchestrating a vicious siege to send all the human beings into the World of Darkness where they will ultimately give up on their own lives). So far, by the end of each season (with exception of the fourth), each of the primary antagonists seems to reform in some way. Kagemaru appeared to see the error his ways, Sartorius was under the Light of Destruction's influence over the whole season, and Yubel had also been driven insane by the Light of Destruction and was freed from it by Jaden and willingly merged with him. Nightshroud was defeated and destroyed by Jaden, but claimed to continue to exist as long as there is darkness in a person's heart.

==Anime==