"My name is Brron, Mad King of Dark World." - Brron
Brron, Mad King of Dark World (voiced by Jamie McGonnigal) was a villain from Yu-Gi-Oh! GX that served as the leader of the Dark World army. When Jaden and his friends went looking for Jesse in the alternate dimension, two of Brron's minions, Silva, Warlord of Dark World, and Goldd, Wu-Lord of Dark World, captured four of them (Chazz, Hassleberry, Atticus, and even Alexis) and used them during his duel with Jaden. Brron used them as sacrifices to for his Wicked Canon spell card in order to create Super Polymerization. However, his plan failed, because he needed 5 offerings (Syrus was the fifth). Even with his friends gone, Jaden continued to duel in sorrow and anger. Jaden won, but the results caused him to become the Supreme King. Brron uses a Dark World themed deck which can discard cards to use various abilities to eliminate the field, or bring out there kind, even draw cards.
During the Adventure series, the memory of his duel with Brron has scared Jaden, making him fear for his friends safety.
- In Jeffrey, Jaden & Friends' Storm Adventures of Rise of the Guardians, Pitch creates a copy of Brron to scare Jaden into fighting back. But Jaden finally conquers his fear of him with the help of his friends.
- The real Brron will return for revenge in Jeffrey, Jaden and Scooby Doo on Zombie Island. He duels Jaden and Jeffrey and uses his Wicked Canon spell-card to trap their friends. His victims included Alexis, Xion, Aqua, Sid, Nails. But Brron looses in the end and gets killed for good.
- Brron will meet Aaron, and Arik in the near future as a duel spirit for Lucifer.