A new character in Persona 5 Royal, Jose (pronounced Joh-zay) is a mysterious boy who appears shortly after the Phantom Thieves enter Mementos. Jose claims to be studying humans for an unnamed person, heavily implying he himself is not human, but taking a similar form to one. Jose believes that by "drinking" humans desires (found in the form of floating flowers scattered throughout Mementos, which he converts to a juice), he will be able to understand more about them.
After Jose's introduction, the player can run over flowers in Morgana's car form throughout Mementos to collect them. Every floor in Mementos will have some flowers and one star stamp location at the end of each floor, with some floors randomly hosting a second stamp stand somewhere else, until all stamps have been collected from the area.
When transitioning to a new floor, sometimes a short cutscene will show Jose speeding ahead of the party in his tiny car, showing that he has parked himself somewhere on the floor. If the player visits him, he will offer items in exchange for a number of flowers gathered, or changing the Cognition of Mementos to increase the gain rate of EXP, money, or items within Mementos. If the player has collected all three Will Seeds from a Palace and defeated the Palace Ruler, he will enhance the collected accessory for free.
If the player collects every stamp within Mementos and visits him on the final floor (on the Path of Da'at), Jose will challenge the Phantom Thieves to an optional boss battle to experience venting his frustrations like a human. During this fight, he can throw grenades carrying any magical affinity, run the player's party over with his car, or launch unblockable fireworks at them. After his defeat, Jose hints that there is another being "observing" humanity, but won't say exactly who or what it is.
Outside of Mementos, Jose makes an appearance in the Thieves Den, breaking through the wall and roughly patching it up with plywood when the player first visits there. He remains in the Den as a tutorial character after that.