Dedede Arena is the final room in the Mt. Dedede stage. It is a boxing ring where Kirby confronts King Dedede at the end of Kirby's Dream Land, it's remake Spring Breeze, and the Revenge of the King follow-up. Its Kirby Super Star Ultra incarnation is a stage featured in Kirby: Triple Deluxe’s Kirby Fighters sub-game as well as the expanded eShop title Kirby Fighters Deluxe and its sequel, Kirby Fighters 2.
The Dedede Arena floor features a diagonal stripe pattern, the background features a portrait of King Dedede performing his peace sign, and the ring is lit by a ceiling light.
The Dedede Arena appears exclusively in the Egg Catcher sub-game. It is largely the same as it appears in Kirby's Dream Land, but has more background details and shows the area to be lit with three ceiling lights.
The Dedede Arena is the final setting of the Spring Breeze sub-game, sporting a revamped in design. The ring now features Dedede performing his peace sign on the floor, the ring being lit by numerous ceiling lights, while the surrounding has bleachers for King Dedede's many followers: Sparky, Laser Ball, Chilly, Mr. Frosty, Sir Kibble, Bronto Burt, Waddle Doo, Scarfy, Waddle Dee, Poppy Bros. Jr., Noddy, Broom Hatter, Cappy, Squishy, Starman, Grand Wheelie, Bounder, Kabu, and Poppy Bros. Sr. In addition to his followers, Mario, Luigi, Peach, Toad, Bowser, and Birdo all make cameo appearances at the sides of the boxing ring. In the background, there is a display that reads "Champion KING DE DE DE VS Challenger KIRBY."
In Kirby Super Star Ultra, the Dedede Arena is altered yet again. King Dedede's emblem is featured frequently in the background, and above the audience are various windows showing the stary sky. The audience features: Cappy, Walky, Broom Hatter, Chilly, Waddle Doo, Sir Kibble, Wheelie, Poppy Bros. Jr., Waddle Dee, Sparky, Bloon, Scarfy, Balloon Bomber, Noddy, Waddle Doo, Squishy, and Snooter. At the sides of the rings are many Toads, with Mario and Peach on the left and Luigi and Wario on the right.
In Revenge of the King, the Dedede Arena changes once more. The ring now features various lightning bolt designs, as well as this battle now being a cage match, with said cage being electrified. In the audience is the lone Bandana Waddle Dee.
Dedede Arena is based on its appearance in Kirby Super Star Ultra. It has a long platform above the main ring, and two elevated areas to the sides. The main hazard of the stage in King Dedede himself. He appears in the foreground briefly, dictating which side of the arena he's going to appear on. After entering the arena, he throws numerous objects at the players, such as Waddle Dees, Apples, Gordos, and oil drums. He can also jump to the other side of the arena, first jumping on the central platform. This is either the fifth or sixth stage played in Kirby Fighters' single-player, and is more likely to be the penultimate stage in Kirby Fighters Deluxe’s single-player. The music that plays here is King Dedede's theme from Kirby's Dream Land 3.