Gem Guardians
From Puyo Nexus Wiki
Ruby Red, Yellow Diamond, Blue Sapphire, Green Emerald also known as Gem Guardians are a series of bosses that appear in Madou Monogatari: Final Exam after Doppelganger Arle and before Phantom God.
Yellow Diamond's expression is sad, Ruby Red appears mischievous, Sapphire Blue is indifferent, and Emerald Green appears to be regularly happy.
