"The Fallen Duke & the Knight Who Hated Him" is a Korean boys' love (BL) manhwa and web novel that blends drama, fantasy, historical, and romance genres. The story centers on Duke Louison, a lord who once deserted his castle during a war and died with bitter regret. After his death, he is given a second chance at life, regressing back to the night of his desertion. Determined not to repeat his past mistakes, Louison resolves to stay and defend his domain at all costs

. In the course of his new life, Louison crosses paths with Carlton, an enemy knight and mercenary known as the "Mad Dog," who harbors a deep hatred for nobility. Carlton, like Louison, has made poor choices that ruined his life. Despite their initial enmity and conflicting backgrounds, the two form a complex and intimate relationship, marked by a mix of animosity and unexpected solidarity. Louison persuades Carlton to accept their harsh reality with the phrase, "If I die, you die too," leading to a bond where Carlton begins to question why Louison helps him so much

. The narrative explores themes of redemption, second chances, and complicated relationships between former enemies, set against a backdrop of war and noble intrigue. The series is noted for its dramatic tension and evolving romance between the fallen duke and the knight who initially hated him