A Sacred Covenant

Prologue： The origin of the war
A fantasy historical novel to depict medieval historay, perceived from a teenager's angle, seems a bit different from those famous writers.
 In 1217, the Andal Empire, located in the northwest of the continent, launched an unprecedented military invasion of the kingdom of Lotland. The invasion came without warning, and the kingdom had no time to organize a large army. The northwest part of the kingdom, except for the fortress of Tran, fell.