The author of the Lord Marksman and Vanadis light novels, Tsukasa Kawaguchi, announced on Tuesday that the series will end with its 18th volume; which is planned for release this year. Apparently, Kawaguchi originally planned to have the series to end with the 17th volume, but decided to extend it.
Kawaguchi started publishing the series in 2011, with Yoshiwo doing the illustrations. FUNimation streamed the 13-episode anime adaptation, which aired in 2014. Lord Marksman and Vanadis was released on blu-ray/DVD with an English dub in February of 2016.
jCafe24 describes the story:
Set in Western Europe during times of war, Eleanor “Ellen” Vertalia, one of the Vanadis of Zhcted, leads the battle into Brune. There are, in fact, seven Vanadis, named for having each received a powerful weapon from the dragon to individually reign over seven territories. The power of the Vanadis invokes dread and fear from their enemies. An earl in the service of the country of Brune, a young archer by the name of Tigre, experienced the Vandis’s power firsthand after being defeated on the battlefield by Ellen. However, Ellen chose to spare his life after witnessing his skills, but in exchange, he is asked to serve her. (Source: jCafe24)