Junko's power is to purify anything, it refers to the refining of substances to remove impurities, such as in the refinement of metals. She used this power on her own grudge, strengthening it such that she became the embodiment of her resentment as a divine spirit, without even a need for an identity anymore. She used this power on Clownpiece and other hell fairies, transforming them into beings of pure life-force that would threaten the Lunar Capital. Touhou