Shizuku Hasei

Shizuku is a maid in the service of Aya. She has been serving Aya since her birth, as is her family's tradition. She is loyal to Aya and is usually cool and taciturn, but she treats Tsugaru with disdain. She carries a special weapon called "Tachikage," which is a combination of a gun and a sword.

(Source: Undead Girl Murder Farce Fandom Wiki)