Toaru Majutsu no Index: New Testament - Volume 9, Chapter 6: Shifting and Fluctuating World. Version_Beta.

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?---

Zavier met Cosmic Consciousness after his death. He was satisfied with every system that Cosmic Consciousness exhibited, so he wanted all of them. Surprisingly, the Cosmic Consciousness obliged him.

Zavier was reborn in an isekai full of magic and alchemy. Now, he had many routes to upgrade. Interestingly, to coordinate these systems, Cosmic Consciousness gave him the gift of being able to duplicate himself. He could clone a finite number of himself to manipulate these systems.

Magus, Alchemist, Mesmer, Tamer, Hunter, Vampire, Werewolf, Dragonknight, Necromancer.....

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By the way, it wouldn't appear NTR or some bullshit harem of courtships. MC of course will have harem but not for cliches.

This is the story of a crazy lich who possesses an internal game system and brings catastrophe to the entire world.

In the fantasy world ruled by Matriarchy, Kael of the Ancient Moonstone House, was working as a guild receptionist. Throughout his life, he was protected by his mother and later, younger sister, who was considered one of the highest potential individuals in the Queendom of Elyria. One day, he hears that his sister has gone missing and his family has accumulated debts of over 127 million gold coins to the Bank. The Queen comes to his rescue, paying off his debts and in exchange, he has to marry her five daughters, who each excel in a domain of their own.Having the five imperial princesses and the Queen herself as the backing, Kael has become one of the most protected individuals in the Queendom. Little did his wives know that Kael had another identity. He is the most dreaded yet noble Assassin of the imperial city, “K,” one who hunts down the criminals who escape punishment either because of insufficient evidence or using their connections.Follow Kael's journey, as he navigates his life as the protected figure in the light and protector of justice in the shadows.