Tsukasa Kawaguchi is a light novel writer born in Japan on February 22, 1979. He is part of the Mystery Writers group in Japan and is best known for the Lord Marksman franchise, the first and most known of the entries being Lord Marksman and Vanadis. Early in development, of the first entry, he planned to have it focus on a young male archer and a female sword fighter as the main characters, that changed when editors of MF Bunko asked for the number of girls to be bumped up from the sole one to a group of seven girls. One of his earliest known works was Leena's World Map which was released in 2009 and centered on a princess working on a map on the behalf of her father. His first two works were War Demon ―Iku-Oni― and Stereotype Power Play, the latter being re-released as Is There a Hero or Savior in This House?!.
Tsukasa Kawaguchi authored the following novels:
- The Broken Sacred Sword and the Sword Maiden of the Imperial Crown
- The Strange Tale of Black Lion Castle (spin-off)
- Is There a Hero or Savior in This House?!
- Kirino-kun doesn't have the lover!?
- Leena's World Map
- Lord Marksman franchise:
- Seraphim Lost (Consists of Parabellum, the Imperial Sword and Ex Libris of the Twin Moons)
- Silver Radiance Knight's Medal
- Thousand and Aegis
- Verte Terra of the Drifting Library
- War Demon ―Iku-Oni―