Joker

Although called the 53rd existence, there are actually multiple Jokers much like in a card deck. If any of them were to win the Battle Fight, it would mark the end of all life on Earth, & the Battle Fight would be reset to begin anew.

Joker

 * Main article: Dirk Trent

Sometimes referred as the Black Joker, he is true identity of Dirk Trent. Technically "wins" the Battle Royale when Giraffa is sealed, but Agema's sacrifice allows Dirk to continue living as a human & need not be sealed, with the Spirit Human keeping him in line. Four years later, after being unsealed by Club Warrior to protect Ada from A-King's assault, Dirk chose to sacrifice himself in order to make Jashin 14 vulnerable for the others to attack; it is unlikely he died however, considering Undead can't be killed. In the series Agema became a Joker to put the Battle Fight at a stalemate, thereby ending it without sealing Dirk.

Albino Joker

 * Main article: Derek Selby

Near the end of the series, another Joker was revealed. This one was white & pink compared to Dirk & is called the Albino Joker by fans. When the fight ended with Agema becoming the Navy Joker, the Albino Joker attacked Crawford to release the Undead from their Rouse Cards in order to restart the fight. It was then revealed that this Joker is the true identity of Derek Selby, who became Kamen Rider A-King to capture all 4 Category King Undead while targetting the King Categories & Ada Chastain to awaken Jashin 14. He was defeated due to the sacrifices of Dirk & Kamen Rider Spade Warrior King Form & is likely sealed.

Navy Joker

 * Main article: Ray Agema

Ray Agema used his King Form to mutate into a Joker, refered to by fans as the Navy Joker in order for Dirk to stay with their friends. His Joker form is never seen but he is seen with a belt with green accents compared to the red ones on Dirk's.