Tsukasa Kawaguchi is a Japanese novelist and light novel author born on February 22, 1979, in Tokyo. He made his professional debut in 2006 after his work, originally titled "Oniko Zoushi," won the Grand Prize at the 18th Fantasia Long Novel Prize. It was subsequently published under the title "Ikusaoni." In the same year, another of his works was also selected as an entry for the 3rd Square Enix Novel Prize. He is a member of the Mystery Writers of Japan.

Kawaguchi has created numerous light novel series across different imprints. Among his notable works are "The Labyrinth Library's Vert-Terra," "Stargazer's Rina," and "The Swords of the Thousand and the Shield Maiden," which ran for a total of 15 volumes. His series "The Silver Radiance Knight Medal" and "The Broken Holy Sword and the Crown Princess" are also part of his broader bibliography. He is credited as the original creator of the series "Lord Marksman and Vanadis."

The "Lord Marksman and Vanadis" series began as a light novel published under Media Factory's MF Bunko J imprint. The first volume was released in April 2011, and the series concluded with its 18th volume in November 2017. The novels feature illustrations by Yoshi☆o for the initial volumes, with Hinata Katagiri taking over as illustrator from the ninth volume onward. The story is set in a fictional European-inspired world and follows a young archer named Tigrevurmud Vorn who becomes entangled with the seven war maidens, or Vanadis, of a neighboring kingdom.

The property has been adapted into multiple media. A manga adaptation illustrated by Nobuhiko Yanai was serialized in Monthly Comic Flapper from 2011 to 2016, with ten compiled volumes. A 13-episode anime television series produced by Satelight aired from October to December 2014. The series has also spawned several spin-off projects. A light novel spin-off titled "Lord Marksman and Michelia" was published between 2018 and 2022. Another spin-off series, "Lord Marksman and Carnwenhan," received a manga adaptation that ran from 2021 to 2023. These adaptations and spin-offs illustrate the sustained popularity of his original work and its expansion into a broader franchise.

Kawaguchi has cited fantasy light novels such as "Record of Lodoss War" and "Fortune Quest" as influences. His body of work is primarily situated within the fantasy genre, often focusing on themes of war, political conflict, and the dynamics between characters from different backgrounds. His career, launched after receiving multiple notable literary awards, demonstrates a consistent presence in the Japanese light novel industry, with several of his series achieving commercial success and receiving multimedia adaptations.