I Leveled up from Being a Parasite, But I May Have Grown Too Much - Chapter 10 - A Boss Appears

What happens when a scientist from a futuristic world reincarnates in a World of Magic and Knights? An awesome MC is what happens! A scientist’s goal is to explore the secrets of the universe, and this is exactly what Leylin sets out to do when he is reincarnated. Dark, cold and calculating, he makes use of all his resources as he sets off on his adventures to meet his goal. Face? Who needs that… Hmmm… that guy seems too powerful for me to take on now… I better keep a low profile for now. You want me to help you? Sure… but what benefit can I get out of it? Nothing? Bye. Hmmm… that guy looks like he might cause me problems in the future. Should I let him off for now and let him grow into someone that can threaten me….. Nahhh. *kill*-

Alternative: Leylin is transported from an advanced technological era into a medieval world— except there’s magic. Equipped with “only” his quick wits and an A.I. chip fused to his soul, he sets out to become the most powerful magus the world has ever known. In a land divided into the Light and Dark Magi, the weak can either be cattle or disposable slaves. Only the strong can determine their lives, and only they have the luxury for virtue. Yet strength is only a tool for Leylin, like any other. His goal, in the end, is his own.

One imperial edict and the family’s calculation, the sweet, adorable her met the cold him that was up high. She became his little princess consort. Everyone said that Prince Ying of Western Xuan Empire was shockingly ugly, cold-blooded and ruthless. They laughed at her that she had mistakenly entered the tiger’s den with her life in danger. But she just laughed that everyone in the world couldn’t see the wider picture, and were stupid and ignorant. The ugly appearance was actually beyond gorgeous, cold-blooded was actually gentle and sweet. She only wanted to hide him away and not allow other people to peep at him. “Big Ice Cube, take off your mask and let this princess have a look!” She propped up her chin with saliva flowing down.

“Want to look?” A certain person’s lips hooked into a devilishly charming smile, saying. “Then first, hand over some down payment…” This is the story of a sweet adorable female and a two-faced male’s journey to fight enemies and kill strange things, while pursuing a romantic relationship that was absolutely full of loving spoiling, hilarity and hot-blooded action.

- Description from Novelupdates

[Highschool Love: The Pain of Romance]A game so cursed no players have completed it.Created to torment the players and have them experience heartbreak by having the heroines constantly getting NTRed by the villain.Everyone advises against playing it.But he was anything but stubborn.Ignoring the spiritual and mental torture from constantly getting NTRed, he persevered, and finally completed the game, achieving the mythical harem ending that everyone said to not exist and regarded as a myth.But before he can celebrate, everything turned black.“You can't protect your heroines, so I enjoyed them. I got to say, they were delicious.”

This story is centered around the man named Yi Ji-Hyuk, who has spent 1000 years in a Medieval Western fantasy-like world before returning back to the modern-day Earth. When he returns, he finds that his home is facing monster threats, and that humans with superpowers have appeared to protect the innocent people of Earth.