The Honoka Series comprises twenty-two identical clone sisters engineered through accelerated growth and compressed mental training. Despite their chronological age, they physically resemble five-year-old girls. All share matching traits: light pink hime-cut hair, brown eyes, slim builds, above-average height, and standard female trainee uniforms. Their genetic origin remains unknown. Created in two batches of eleven, they serve as Garde pilots aboard Sidonia. En (pilot of TS203/703) initially despises Nagate Tanikaze, convinced he spied on the sisters during a changing incident. Her hostility persists even after recovering from severe combat injuries, reigniting when Nagate interrupts her and Ren during photosynthesis. Ren (pilot of TS206/706) witnesses sister Hou's death against Benisuzume and nearly dies herself before Nagate saves her. Ren grows to trust Nagate and seeks to mend En's animosity. Hou (pilot of TS205/705) becomes the first Honoka casualty when Benisuzume annihilates her cockpit in one strike. Shou (pilot of TS029), the 22nd sister and most skilled of the second batch, meets tragedy during a Lem star system expedition. Absorbed and replicated by a Gauna, she transforms into a hybrid, enduring an existential crisis while retaining her personality until the Mizuki's crew euthanizes her to end her suffering. Other identified sisters include Ro (unit 707), Hou (unit 708), Baku, Kou, Tou, Ou, Ryou, Sen, Kun, Rin, Sui, Kei, Nen, Sou, Shoku, Shi, Raku, and Kan. En and Ren both develop romantic feelings for Nagate, complicating their roles as pilots.