Kisaki Matsuribi is a supporting character in the Aldnoah.Zero television series, introduced as a seventeen-year-old student at Shinawara High School who is one year senior to protagonist Inaho Kaizuka and his friends. He is a classmate and close friend of Yutaro Tsumugi, with whom he shares a playful dynamic, often affectionately calling him Yutaro-chan and occasionally attempting to hug him, though these gestures are typically rebuffed. His personality has been described by original character designer Takako Shimura as having the image of a frivolous man. Kisaki speaks with a distinctive verbal tic, often ending his sentences with ~imda. Compared to Yutaro, who is portrayed as an otaku with a notable interest in yuri, Kisaki maintains a slightly lower profile among the group of friends.

When the second war between the Earth Alliance and the Vers Empire begins following the assassination of Princess Asseylum Vers Allusia, Kisaki is among the students drafted into the United Forces of Earth. He initially participates in search and rescue operations for civilians needing evacuation from Shinawara City under the command of Koichiro Marito. Following this, he serves as a communications officer, or radio operator, aboard the amphibious assault ship Wadatsumi under the command of Darzana Magbaredge. His duties involve guiding friendly Kataphrakt units onto the ship's deck and maintaining communications during combat operations. When the Wadatsumi is attacked and nearly sunk by the Martian Kataphrakt Hellas near Tanegashima, Kisaki successfully transfers along with the rest of the crew to the Deucalion, the Earth forces' advanced flying battleship. He continues to serve as a communications operator aboard the Deucalion throughout the latter part of the series. His official rank is eventually revealed to be corporal, a standard designation for the conscripted student soldiers excluding special cases like Inaho.

Kisaki does not possess any special combat abilities, Aldnoah-related powers, or a personal Kataphrakt. His role is consistently that of a support crew member rather than a frontline fighter. Throughout the story, his character does not undergo significant development or personal transformation, remaining a steady and reliable, if relatively low-profile, presence among the young conscripts. His primary motivation is survival and fulfilling his duties to his unit and comrades. His key relationships include his friendship with Yutaro Tsumugi, his respect for his commanding officers Darzana Magbaredge and Koichiro Marito, and his camaraderie with the other students from Shinawara High School, including Inaho Kaizuka, Inko Amifumi, and Calm Craftman.