Yoku Hokke occupies the third position among the five Hokke sisters, situated between Maika and Kanashi in their family lineage. After their parents abandoned them and later died, Yoku and her sisters endure severe poverty while pursuing their father's final directive to become "excellent evil." She joins the Gedou Otame Tai (Heretic Girls Squad), a magical girl unit committed to spreading villainy, though their endeavors consistently backfire into unintentionally benevolent or heroic results due to their inherently gentle dispositions.

As a wielder of earth-aligned elemental powers within the team's classical elemental framework, Yoku channels this affinity through terrain manipulation during combat and transformation sequences. Her speech and incantations feature the recurring verbal motif "Banana Banana," a signature quirk reflected in her dedicated character theme "Bananan BANANA ♪ Yoku" on the series soundtrack.

Teenaged Yoku participates in the squad's misguided evil plots, all of which ironically yield helpful outcomes. This perpetual failure underscores her core contradiction: a genuine dedication to wickedness clashing with an innate kindness. Her narrative revolves around this unresolved tension between familial duty and natural compassion, without significant evolution beyond this dynamic. She functions within the ensemble, reinforcing their comedic role as accidental heroes.

Her relationships center on sisterly bonds, demonstrated through collaborative misadventures and shared hardships like financial struggles and part-time work. No individual relationships or personal history beyond the collective family experience are detailed. Yoku appears consistently across every episode, including the merged storyline in the finale where the team unites against a shared adversary.

Her portrayal remains exclusive to the 13-episode television series.