Lambert, one of the great generals from Regios kingdom, was suspected for planning a rebellion against his lord at the end of unification war, and he died an unnatural death. Two hundred years later, when the era had changed and Regios kingdom had entered its peaceful era, he accidentally revived as a demon called Undead Knight… Lambert, whose entire body was wrapped in a flashy Demon Metal[Organ], set out on a journey to punish the wrongdoers while enjoying the peaceful sight of Regios kingdom. But… This peaceful era was basically an easy mode for Lambert, the greatest general of the chaotic era.

Other Version :

Betrayed and assassinated by his lord and his best friend, Lambert’s soul was unable to ascend to the heaven.

Two hundreds years later, he was revived as an undead. After finding out that the one who betrayed him has long since died, Lambert decided to take a trip around the kingdom.

Follow Lambert’s journey in his second life as an undead to seek for his own salvation as he kicking the ass of the villains along his journey.

P.S. – Organ is supposedly very heavy