Death March kara Hajimaru Isekai Kyusoukyoku (WN) - Book 15 - 15-42. Mastermind

In his previous life Bai Lang was a small star. He rejected his boss and stupidly engaged in a relationship which he thought was true love.

He didn’t expect that he would get betrayed, die of a heart attack and trouble his boss to accompany him on his last journey.

After his rebirth, he decided to give up on true love. As for his boss… since he wants something then just let him have it ba.

So this little star after his rebirth collected his boss, and then it became a true love story with his boss.

In between there are good friends/love rivals/scum men in the mix. A sweet story with a happy ending.

- Description from Novelupdates

In a fractured world ravaged by the collision of dimensions, humanity faces an apocalyptic threat from three fronts—vengeful ghosts from the past, sinister alien invaders from beyond the stars, and rogue artificial intelligences that have turned on their creators. Amid the chaos, a resistance rises, blending human courage with AI innovation to battle the horrors plaguing the Earth.Leading the charge is Elara Myles, a brilliant yet haunted survivor who holds a mysterious nexus device—one that connects to a realm between the living and the dead. As the veil between dimensions thins, Elara must confront phantom enemies and inner demons while uncovering the secret behind the Nexus—before it becomes humanity’s doom.With every heartbeat, the war intensifies. Ghosts whisper secrets, machines evolve with emotion, and the skies rain down terror. In Phantom Nexus, survival isn't just about fighting back—it's about understanding the enemy that once was us.

Kael Veyne was betrayed, hunted, and left for dead in the depths of the Abyssal Dungeon.As an infamous assassin, he was the empire’s deadliest shadow—until the day his guild turned on him.Ambushed in the Abyssal Dungeon, his body was torn apart, and his soul was consumed by the abyss. But death was not the end.He reincarnates 25,000 years later with the Devouring Bloodline System. Kael awakens in the body of a noble scion sharing a similar name to him, and his very essence fused with eldritch power.With every kill, he absorbs primal energy, evolving into something far beyond human. Monsters, mages, mancers, knights, assassins—nothing is beyond his reach.