Once Bitten, Twice Shy - Chapter 247 - Special Day

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

Rein Aster was just a herbalist farmer from a border village.A nobody. A background NPC in a story filled with prophecy and divine warfare.But by chance—or fate—he saves one of the 7 Demon Lords during a catastrophic war event. Instead of killing him, she falls for him.Obsessively. Violently. Eternally.And then… so do the others.Each Demon Lord tries to trap Rein as her personal lover/pet/priest/husband/god, building dungeons, illusion palaces, soul prisons—but Rein keeps escaping. Quietly. Cleverly. Never fully rejecting them—but never submitting, either.Why?Because Rein realizes something:The gods are worse than demons.The heroes are tyrants in shining armor.The world is collapsing—and he’s the only one they all listen to.So he hatches a plan:Use the Demon Lords’ love to take over the world.Pit them against the heroes. Unleash them on the gods. Make them fight for him. Make them kill for him. Then tame them all.Not as a king.Not as a savior.But as the lover they would burn the world for.__________The yanderes here are darker than what you might be used to.You have been warnedThe entire novel has a dark feel. Atleast read the first two minor arcs

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.....

-----

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

Lu Zhengfei personally killed Chen Qianqing with his abuse.

He cut off Chen Qianqing’s legs, and blinded his eyes, locking him up with chains in his house. Then, he watched with his eyes wide as he died. Injuries inflicted in the name of love would always end in a tragedy.

Did Lu Zhengfei regret it? Of course he did. And so, God gave him a chance to be reborn.

But this time, he found that he himself——became Chen Qianqing.

- Description from Novelupdates