Guardian Machine is an optional boss that appears in the Final Night of the Inaba Pride Exhibit, replacing Best Friend. It is the subject of the request "Investigate the Inaba Pride Exhibit," where the party must defeat it in order to obtain the Red Orb, called the Sphere of the Altar by Elizabeth, from the void behind it. Completing the request rewards the Almighty Badge accessory, which increases HP and SP by 100 and all stats by 10. When defeated, it may drop Machine Gold. Machine Gold is used to create the Curse Blade for the P3 hero, the Setsugetsuka for Junpei and the P4 hero, the Hammer of Repose for Shinjiro, and the Moth Fan for Yukiko.
After the request is completed, it will continue to respawn whenever the party revisits the Labyrinth.
Persona Q2: New Cinema Labyrinth
Guardian Machine appears on the lower levels of A.I.G.I.S Like the other giant rare Shadows in the previous Labyrinths, it is protected by an Affinity Barrier, and drops additional amounts of money when struck while the Barrier is active. The Barrier breaks once it reaches half health and is the last enemy standing, exposing its weakness to Ice and Nuclear attacks. The Shadow itself has two actions per turn, and will preferably spend its first one setting up a buff before using its second to attack.
When defeated, it may drop Machine Core, Grandiose Armor, Machine Metal. Machine Core is used to create the Ion Saber for Akechi, the Morph Axe for Haru, the Furinkazan and Bishamonten* for Chie, the Drowsy Shield for Kanji, and the Capital Robe female armor. Grandiose Armor is used to create the Soul Potpourri and Courage Fob accessories. Machine Metal is used to create the Night Stalker* for Shinjiro and the Tech Dog Suit for Koromaru.
Persona Q: Shadow of the Labyrinth
For most of the fight, Guardian Machine will use Physical skills to attack the party. However, when "its eyes start shining," the party should defend, as it will proceed to use Mind Charge followed by Megidolaon. Inflicting Magic Bind or Panic, while difficult, will block out this troublesome phase and allow the party to spend fewer turns on the defensive.