DRAGON QUEST XI - Easy Way to get Metal Slime Swords (Guaranteed Drops from Hyperpyrexions)

Hyperpyrexion's rare drop is a Metal Slime Sword. Do the Haulellujah pep power move with The Luminary, Erik, and Jade, and you get an enemy's rare drop as a guaranteed drop after the battle.
I fought them at Gallopolis Region - Celestial Sands.

DRAGON QUEST® XI: Echoes of an Elusive Age™