Zakuro Mitsukai is the younger sister of Dokuro Mitsukai. Chronologically nine years old, she possesses a significantly more mature physical appearance than her sister, including greater height and bust size. Originating from the same future timeline as Dokuro, she is an angel of the Lulutie order, exhibiting inherent superhuman strength and endurance. Her standard attire features a modified naval officer's uniform and an eyepatch covering her left eye. Zakuro consistently displays a calm, soft-spoken, and polite personality, formally addressing others with "-san." This composed demeanor starkly contrasts with Dokuro's volatile nature, positioning Zakuro as the "Girly Girl" in their sibling dynamic.

Her primary weapon is the versatile wet towel "Eckilsax." Zakuro wields it with proficiency and elegance; Eckilsax can split into multiple sections for close combat or extend to bind opponents effectively. Following the first season's events, Zakuro moves in to reside with Sakura Kusakabe and Dokuro during the second season. She maintains a generally amicable relationship with Sakura, though her interactions occasionally include moments where she suggests Dokuro should kill him. Zakuro promptly apologizes after such remarks. Her function within the narrative centers on her presence as Dokuro's sister, her residence with the main characters, and her participation in comedic and violent scenarios involving Sakura.