Sister Tonia’s holy weapon allows her to offensively utilize her blood hence the numerous cuts on her arms to facilitate its use. While typically used as a layer of near-impenetrable armour, if she focuses it in a single point, she’s able to fire it at high speed as a finisher to pierce through the hardened cores of most devils hence her nickname.

Using that wastes blood though so naturally anemia and usage time are her biggest enemy and thus her appearances on the front lines drastically reduced as she got older. Nowadays she’s only called when the church needs a mission supervisor for the younger executioners, otherwise she’s content to serve as her best friend Claudius’s administrative right hand at his convent (a glorified way of saying she’s lazing away in pseudo-retirement while playing house with young Almonde and Mikhail)

Source: https://www.pillowfort.social/posts/3870836