Douluo Dalu 2: The True God King - Chapter 214: [DD2]:

Michael was suddenly reborn into a another world by a God because of an accidental death. To make up for this fact, the God gave him another life in a fantasy world of swords, magic, and monsters.Unfortunately, it turned out that the world he was reborn into was still stuck in the medieval times. It didn't have electricity, it didn't have proper plumbing, and it didn't have any technology that he was so used to back in his old world.But thanks to the God's blessing and an AI assistant called ChatJK1, he was given the power to MAKE his life comfortable. Slowly, Michael transforms this new world into a place even better than his previous one by taking ideas from the modern world and putting it in this world, with the added bonus of magic.

“I thought I was becoming powerful, but it never occurred to me I was inching closer to the abyss.”

***

The Blue Planet: Earth.

Shane was living a beautiful life. He was a topper in his university. Girls flocked around him like birds and bees. His friends treated him as some God.

Everything was good until he was electrocuted.

If you are wondering if his adventures have ended, you're wrong. This was just the beginning.

The next moment he opened his eyes, he became something he never dreamt of—a system. Wait, why wasn't he a host instead?! Wouldn't people enter into amazing fantasy worlds with a cool system after dying?

Why did he have to wake up in a white room?!

He thought everything would be fine even after becoming a system. What could go wrong when he just had to sit behind the desk and handle different hosts?

Boy was he so wrong.

He could use Dark Cosmic Energy! Something only demonic beings could use!

What was going on? He was a human being in his previous life! How the heck could he use demonic power?

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Sneak peak~

“D-Destroy….” Shane's mind buzzed as he thought of something, “Y-You don't mean…. I-I have to destroy an entire world?”

“No,” When Ed said that, Shane's shoulders relaxed as if he had been unburdened, only to freeze again after hearing the next words: “You have to destroy worlds.”

“Can you be useful to me?”

“I… I can be…”

The first time they met, she knelt trembling before him, begging for shelter. The slave caught his interest, and he brought her back to his palace.

She could’ve never imagined that in one night she’d go from a spoiled little slave princess of a defeated kingdom, to becoming a powerful prince’s pet.

He kept her by his side… spoiled her, cared for her, loved her, and gave her meticulous care and high status. Whatever she wished… she could do so under his name.

But, she angered him and chose to run away. He captured her within a day.

“Don’t forget, my little dearest, everything I have given you can be taken back…”

In a spur of anger, she hit him, her feeble hands striking against the flesh of his cheek. Gnashing her teeth in anger, she said, “Do you have the ability to take my child back?!”

- Description from Novelupdates

Kanda Kyoichi transmigrated to Konoha and became a temporary instructor at the Ninja Academy. Fortunately, he awakened the Mentor System.By teaching others, he could earn rewards.Thus began Kyoichi’s career as a “teacher” in the ninja world.Shisui: “Sensei’s unique interpretation of the Will of Fire has given the Uchiha Clan a true sense of direction!”Asuma: “The essence of the jade lies in protecting the people, with the advanced leading the way for the less experienced. Only then can Konoha become stronger!”Kakashi: “He’s my life mentor. He transformed Konoha!”...Years later, in the memoirs of Kyoichi, now the Hokage, he wrote:“I honestly just wanted to be a life mentor!”