Story
A millennium ago, the Blue Moon Kingdom was engulfed in an endless war due to internal conflicts. On the verge of total destruction, the Kingdom was saved by the hands of a masked hero called the 'Red Man'. The survivors exiled the militants who started the rebellion and established the "Blue Moon City", a magnificent civilized paradise led by a large corporation. Unfortunately, for an elementary school teacher, Mr Kim, being the descendant of the infamous tyrants meant living in the impoverished slums. Although he had nothing to his name, he held his students very close to his heart.
Synopsis via AniList (English).
