The Black Moon Clan palace, also known as the Black Moon Clan castle is the interior of Prince Diamond and his younger brother Prince Sapphire, which serves as they secret hideout and hidden citadel. This battle arena made its first debut in the second season of Sailor Moon series. It is also called Prince Diamond's castle, Prince Diamond's palace, and Prince Diamond's fortress.
Prince Diamond and his younger brother Prince Sapphire needed a remote base of operations for their newly reformed Black Moon Clan. After a long search, the two siblings found this abandoned Christian church and immediately claimed it as the new home of the Black Moon Clan.
In Sailor Moon X Teenage Mutant Ninja Turtles, the Black Moon Clan palace features various arena interactions. From farthest left to right, they are:
- A dragon statue, which can be jumped off of in the air in order to escape from the opponent.
- Marluxia's scythe, which can be used to swing at the opponent with it.
- Sister Lucia's ring blade, which can be used to throw at the opponent with it like a shuriken.
- Sir Enoch's steel kite shield, which can be used to throw at the opponent with it like a boomerang.
- Vento's war hammer, which can be used to smash the opponent by the skull with it.
- Sister Agnes Sanctis' lotus wand/staff, which can be used to strike at the opponent with it.
- A violin that can be used to hit the opponent by the head with it.
- A lit candle stand that can be used to swing at the opponent with it, thus setting them on fire.
- Homura Akemi's black knight circle shield, which can be used to throw at the opponent with it.
- Demyx's water guitar, which can be used to bash the opponent by the skull with it.
- A battleaxe, which can be used to strike the opponent by the head with it.
- A mace, which can be used to smash the opponent by the head with it.
- A war hammer, which can be used to bash the opponent by the skull with it.
- In Sailor Moon X Teenage Mutant Ninja Turtles, Sunset Shimmer's crown, Sayaka Miki's sword, Jafar's king cobra snake staff, Sailor Pluto's staff, Sailor Mars' long bow, Sailor Venus' whip sword, Kyoko Sakura's spear, Madoka Kaname's long bow, Ryu Hayabusa's sword, Mami Tomoe's matchlock, Octavia Melody's violin, Michelangelo's orange bandanna, Donatello's purple bandanna, Leonardo's blue bandanna, Raphael's red bandanna, Princess Luna's necklace, Starlight Glimmer's staff, Larxene's kunai knives, Raphael's sais, Vexen's ice kite shield, Zexion's spell book, Princess Luna's crown, Axel's double ring blades, Twilight Sparkle's crown, Xigbar's double pistol swords, Shuyin's sword, Tidus' sword, Sister Angeline's kunai knives, Xaldin's lance, Demyx's water guitar, Tiger Claw's sword, Princess Celestia's crown, Rikku's hunting daggers/knives, Paine's sword, Tiger Claw's matchlock, Homura Akemi's black knight circle shield, Rojo's matchlock, Gary's black sunglasses, Maleficent's staff, Myles Standish's matchlock, Sephiroth's katana, Leonardo's ninja swords, Fong's meat cleaver, Cloud Strife's buster sword, Zachary Fair's buster sword, Casey Jones' hockey gloves, Hun's black sunglasses, Michelangelo's double chained-sickles, Ho Chan's hunting knife/dagger, the Shredder's claws, the Shredder's helmet, Tsoi's purple headband, Marluxia's scythe, Karai's ninja sword, Mulan's sword, Donatello's staff, Casey Jones' hockey stick, Shan Yu's sword, Shishio Makoto's sword, Kenshin Himura's sword, Vincent Valentine's pistol, Yuffie Kisaragi's giant shuriken, Aerith's staff, Seta Sojiro's sword, and Saix's sword can be seen in the background.