- "So the school's a castle, and the students are slaves... It's so on point that it makes me laugh. This really is the inside of that asshole's head...!"
- —Ryuji Sakamoto, Persona 5
- Background Music: "King, Queen, And Slaves" (and its Another Version)
- Available: April 11 (tutorial), April 18 (mission)
- Deadline: May 2 (Protagonist, Ryuji and Mishima getting expelled)
- Owner: Suguru Kamoshida
- Location: Shujin Academy
- Keyword: Castle
A world within the Metaverse created by Suguru Kamoshida. The Palace transforms Shujin Academy into a castle, reflecting Kamoshida's belief that he is the king of Shujin Academy. The Palace is guarded by knight shaped shadows.
After Shiho Suzui's suicide attempt, the Phantom Thieves of Hearts plan a heist to steal Kamoshida's heart in order to prevent the protagonist's's expulsion. Shadow Suguru initially imprisons the protagonist and Ryuji Sakamoto within, where they meet Morgana, who explains the other "students" in the jail cells and Suguru's harem are Cognitive existences who are not the actual person, but replicas born from how Suguru views the volleyball team-ie, as slaves to do his bidding and increase his prestige, or sex objects.
Kamoshida's Treasure in reality is his Olympic gold medal, which takes the shape of a royal crown in the Metaverse. The Phantom Thieves sell the medal to Munehisa Iwai for 30,000 yen and use that money to celebrate with a buffet at the Wilton Hotel in Shibuya. The player receives 6,000 of the remaining yen for their own personal use.
- Bicorn (Morgana's Awakening)
- Eligor (Ryuji's Awakening)
- Belphegor (Ann's Awakening)
- Suguru Kamoshida (Asmodeus)
- Trophy of Obsession
- Kamoshida's Palace is likely a reference to Yukiko's Castle. It has black-and-white checkered floors and a red carpet with gold edges. However, instead of a princess searching for her "prince", it is now a king searching for his queen.
- The way all male student prisoners are tortured with cruel physical training machines alludes to Michiko Matsudaira's abuse to two physically incapable male schoolmates (Kenta Yokouchi and Tsutomu Kurouri) in the Snow Queen Quest of Megami Ibunroku Persona.