Mementos has one main platform with a slant in the middle, similar to Meta Crystal, with two pass-through platforms over the center and the left side. A third platform with a cracked screen occasionally appears on the right. Trains periodically appear in the background, the set below the stage being able to damage fighters. If a fighter is hit by the front of a train, they will take much more damage than usual, and trigger a Special Zoom effect. Occasionally, a large triangle-shaped wall appears at the top or on the sides of the stage. The trains and the walls usually never appear at the same time, though they can appear at the same time when walls appear above the stage. When players run through the stage, they'll splash purple ink-like liquid with each step.
The stage's main design, based on Persona 5, uses a predominantly red color scheme, with star designs and black-and-white halftone motifs. If a song from Persona 4 or Persona 3 is playing, the stage will change design to reflect the respective game's design motifs. For Persona 4 songs, the color scheme changes to yellow, the floors and background seats are not cracked, the platforms incorporate flowers and checkerboard patterns, and the backdrop includes rainbow-like streaks. For Persona 3 songs, the color scheme changes to blue, the platforms incorporate clocks and triangular patterns, and the backdrop includes a full moon. If Joker wins a match on Mementos in one of these alternate designs, his victory pose screen and victory music will match Mementos. Joker's Rebellion Gauge will also change color to match that of Mementos. If Stage Morph is on, the victory screen will reflect the most recently visited version of Mementos. If the match ends before Mementos is visited, the screen will have the default Persona 5 theme.
The Morganamobile occasionally appears in the background with a "meow" sound, dropping off the other Phantom Thieves of Hearts. When a fighter is defeated, they will occasionally call out in praise. Their names are as follows;
Ω form and Battlefield form
The Ω form and Battlefield form is set on a completely flat version of the normal form's main platform that is also resized and reshaped to match Final Destination and Battlefield, respectively. The train hazard is absent (although one still travels in the background periodically), and the platforms in the Battlefield form are based on the one from the main stage. The Morganamobile still brings the other Phantom Thieves of Hearts to the stage. Likewise, changes to aesthetics and Joker's victory screen caused by music selection will still be applied as well.
With hazards off, neither of the floating platforms appear on the right side, the walls and ceilings that periodically appear are removed, and the trains are absent. The Morganamobile still brings the other Phantom Thieves of Hearts to the stage. The stage can still change its theming if Persona 3 or Persona 4 music is played.
Mementos is a location that is visited several times throughout Persona 5. Part of the mysterious Metaverse, it is the Palace of the collective unconscious. Located under the subway tunnels of Shibuya, it is lined with train tracks and train platforms that Shadows, the game's enemies, use to traverse the dungeon. As it would be infeasible to traverse the massive dungeon by foot, the shapeshifting Morgana transforms into a car and has the protagonist drive him when exploring it.
The Phantom Thieves are able to visit Mementos in order to take requests to change the hearts of people whose distortions are not bad enough to cause their own individual Palace to manifest. Exploring Mementos' randomly generated floors also offers the opportunity to gain money and EXP, as well as capture Personas that the player may have missed in a previous Palace. An entrance to the Velvet Room is conveniently located at the entrance to Mementos, allowing a player to summon or fuse new Personas.
As the Phantom Thieves' notoriety increases and the game progresses, they are able to explore more and more of Mementos.