Mallybath Blackball, a witch serving under Stiyl Magnus within the Anglican Church, forms part of a trio with Marie Spearhead and Jane Elves, the former leading their operations. Self-taught but hindered by stagnant magical growth, the group sought Stiyl’s expertise in rune magic. Though she sarcastically refers to him as “teacher,” her tone lacks genuine reverence.

Her practical attire—a bowler hat adorned with a ribbon, shoulder-length wavy brown hair, a loose robe, breeches, and white stockings—diverges sharply from her teammates’ more stylized outfits, prioritizing utility. Initial designs envisioned a doll-like aesthetic, later refined into a detective-inspired motif to enhance visual distinctiveness.

Serious yet prone to naivety and clumsiness, Mallybath struggles in combat, often requiring Stiyl’s rescue during missions. Specializing in earth manipulation via a feather pen, she conjures eruptive rock traps and coordinates attacks with her allies. Her magic allows indefinite subterranean concealment and earth pillar creation, though dependence on direct ground contact restricts her tactical flexibility.

In the film’s events, she aids in surveilling and abducting Arisa Meigo. Her earth-based assaults face repeated setbacks, notably nullified by Kamijou Touma’s Imagine Breaker. Later, she supports Stiyl’s infiltration of the Endymion space elevator to disrupt Ladylee’s schemes, though impulsive actions during clashes force him to intervene and avert harm. Post-mission, she recuperates alongside her team while sharply rebuking Stiyl for unspecified grievances.

Her documented involvement remains confined to these events, with no expansion into other media or narrative extensions beyond the film’s scope.