Inferno Island

Inferno Island, also referred to as Infernal Island, is a court in Mario Tennis Aces that takes place in a volcano area. It mostly consists of an arch over some lava. The court's gimmick is Mechakoopas that exit out of holes and meander around the court before momentarily exploding. The court has a fast ball speed and the strongest bounce strength in the game, and takes place outside Bowser's Castle. On this court, Mechakoopas act as line judges and a Parabones acts as the referee, while Goombas, Koopa Troopas, Koopa Paratroopas, Hammer Bros. and Sledge Bros. spectate.

In-game description

 * "Bowser's Castle, built on a blazing island surrounded by hot lava. Those Mechakoopas are too hot to handle!"

Adventure Mode
In Adventure Mode, Inferno Island is the sixth area visited. It is the resting place of the final Power Stone, and Mario and Toad come here hoping to obtain it before the Lucien-controlled Wario and Waluigi do. When they arrive on the island, they are confronted by Boom Boom, who won't let them pass unless Mario defeats him in a tennis match. This opens up access to the Castle Bridge and Castle Practice Court, where Mario can attempt to hit 30 shots past a Chain Chomp or score 1,000 points in a panel challenge, respectively. Both of these missions are optional; completing the latter rewards Mario with the Flame Racket. Upon arriving at the Castle Gates, Mario must take down a horde of Bowser's minions to gain entry to Bowser's Castle. The Power Stone is guarded by a Bowser Statue. However, after it is destroyed, the Power Stone is discovered to have been stolen by Wario and Waluigi, who took it while Mario and Toad were distracted. This forces Mario, Peach, and Daisy to compete in a tournament with Lucien's puppets for the remaining Power Stones.