Starting on April 27, 2018 at 10am JST, Persona 3, Persona 4, and Persona 5 characters will be crossing over into Puzzle & Dragons for a collaboration event in Japan. The event will last until May 11, 2018.
Here are the characters that will appear for the collab, according to the official site:
Mitsuru Kirijo and Aigis:
There will also be a collaboration dungeon where enemies such as Pixie, Jack Frost, Cerberus, and King Frost will appear. By beating the dungeon many times, players can receive Caroline and Justine as a unit:
At the Monster Exchange, Morgana will be up for keeps as well:
Finally, the Persona collaboration will also be extending over to Puzzle & Dragons Radar as well.
Puzzle & Dragons is available on iOS and Android.