Haruka Saigusa features in the crossover series Kaginado as a chibi adaptation of her original incarnation from Little Busters!. She appears alongside characters from various Key franchises including Kanon, Air, Clannad, Rewrite, and Planetarian, maintaining her established background, personality, and narrative trajectory from Little Busters! media. In Little Busters!, Haruka attends high school as a mischievous student who habitually clashes with the disciplinary committee, especially her twin sister Kanata Futaki, the public morals chairman. Skipping classes and instigating disturbances earns her the "Troublemaker" moniker. Beneath this rebellious facade, she displays steadfast loyalty to friends and aptitude for repair work. Her family history involves profound trauma. Haruka and Kanata originate from the Saigusa clan, which practiced a tradition of dual husbands marrying one wife. Their biological father, Shou Saigusa, committed murder while fleeing this system, resulting in the twins' upbringing by the Futaki branch family. Designated the "inferior" twin, Haruka endured abuse while Kanata faced pressure for perfection, fueling Haruka's resentment and deliberate efforts to tarnish the family name. Her character development revolves around confronting this past. Initially, she pursues her biological father's identity, believing it will resolve her self-worth struggles. Assisted by Riki Naoe, she investigates Shou and uncovers inconsistencies in Kanata's behavior, leading to a confrontation that reveals Kanata's suffering under the Futakis. The sisters reconcile, rejecting a blood test to determine parentage as they transcend their familial trauma. Haruka achieves emotional growth by realizing hatred is unnecessary and embracing self-acceptance through bonds with others. Physically, Haruka has violet hair styled in two side ponytails, blue eyes, and stands 163 cm tall. She wears her school uniform with distinctive patterned thigh-high stockings. Left-handed, she works part-time in the school cafeteria baking sweets and refers to herself in the third person using the nickname "Haruchin".