Shi ni Modotta Mob wa Last Boss no Saiai deshita

Kreis, the son of a powerful marquess, harbors a secret: he is actually a modern-day Japanese man reincarnated into the world of a boys' love novel that he himself authored. Tragically, his memories of his past life do not surface until after he has already been cast as a villain and executed as a mere lackey to the story's final boss. Miraculously granted a second chance, Kreis finds himself sent back in time before his tragic fate can unfold. Armed with the knowledge of his own creation, he vows to exact revenge upon the family that mistreated him while pledging his absolute devotion to King Siegfried, the breathtakingly beautiful final boss. Despite Siegfried's role in the narrative, Kreis feels an overwhelming, inexplicable compulsion to protect the king at any cost. As the timeline shifts, Kreis realizes that all the central characters of his novel—including his younger brother, the story’s original protagonist—are destined to gather at his upcoming birthday party. With King Siegfried now standing by his side, Kreis faces a critical turning point. Together, they must navigate a treacherous web of predetermined events as Kreis fights to shatter the rigid confines of the plot he once wrote and forge a new destiny entirely his own.