The manga series KissXsis, which the anime is based on, began serialization in Kodansha's magazine.
The anime adaptation of KissXsis aired on television, bringing the manga to a wider audience.
The original video animation (OVA) episodes of KissXsis began release, continuing the story beyond the TV series.
Keita Suminoe moves back home from boarding school to live with his older stepsisters, Ako and Riko, marking the beginning of their complicated sibling relationship.
Ako and Riko openly express their romantic feelings toward Keita, setting the premise for ongoing comedic and romantic situations.
Keita begins attending high school, introducing new characters and expanding the setting beyond the home environment.
Keita and his stepsisters participate in the school's cultural festival, leading to various humorous and heartfelt moments.
The sisters engage in a series of playful competitions to win Keita’s favor, intensifying their sibling rivalry with romantic undertones.
Keita develops friendships and deeper connections with other girls from school, adding complexity to his relationships.
The Suminoe family goes on a hot springs trip, creating opportunities for character development and relationship dynamics outside school.
Ako comes to understand the depth of her emotions and begins to reconsider her approach towards Keita and Riko.
Riko provides emotional support to Keita during personal struggles, strengthening their bond beyond rivalry.
