Korean press has compared Lee's the "Bird" series to J.R.R. Tolkien's Middle-earth works, in the aspect that Lee constructed languages and created geography, vegetation, and history that pans several thousand years. "Moreover, unlike Tolkien who set the virtual history simply as a mythical battleground of good and evil, in Lee's world the moving history, politics, industries and cultural background are constructed in such great detail that this another world feels real and urgent, and sucks you in." The Korean overtones of the world was also acclaimed. The ancient language of Arajit is based on the Proto-Korean language. The undefeated general Elsi enjoys a game of baduk while other characters enjoy traditional Korean folk games such as Ssireum and Yut Nori, and Jeong U dresses in what is similar to Hanbok and wears a binyeo in her hair. The Empire's system of rank and office is modeled after that of Silla and Goryeo.