Destroying My Own World - Chapter 401 Eternal Life.

Alex was an ordinary teenager—until the day he discovered his ability to drain energy from the dead. With powers rooted in death itself, Alex hides his necromancy behind a normal life, secretly entering deadly portals to fight monsters and earn money. But beneath the surface, a darker truth lingers—his parents's death and his powers are linkedAs he harnesses his necromantic abilities, draining the fallen to grow stronger, the weight of his power begins to take its toll—and the line between the living and the dead starts to blur.With enemies closing in and betrayal around every corner, Alex must master his growing abilities before they consume him—or worse, before the forces hunting him claim everything he has left.When death becomes your greatest weapon, how long can you survive before it turns against you?---

I finally managed to kill the demon lord.