Blade of the Phantom Master

In a land where the once-mighty kingdom of Jushin has crumbled into chaos, a jaded warrior named Munsu roams the wastelands. When he collapses in the desert, he is rescued by Mon-ryon, an earnest young man who still believes in the ideals of their fallen nation. Mon-ryon seeks to join Jushin's legendary secret agents and rescue his beloved from the clutches of a tyrannical warlord who now rules the region. Though initially reluctant, Munsu finds himself drawn into the quest, compelled by circumstances and his own mysterious past. As they journey together, Munsu demonstrates his unique abilities as an Angyo Onshi - a special agent with supernatural powers tied to Jushin's former glory. Along the way, they encounter various threats in this dangerous new world where survival is never guaranteed. Their path leads them to cross swords with corrupt officials, supernatural threats, and the remnants of what Jushin has become. As Munsu continues his travels, he is joined by allies who share his vision of bringing justice to a land overrun by chaos, each with their own reasons for following the last Angyo Onshi. (Source: AniDB - edited for spoilers)