Sin System: Demonic Harem After Reincarnation

After suffering a heat stroke, Blake, a hardworking but poor university student, mysteriously acquires a high-tech system. Overnight, his mundane university life transforms into a whirlwind of success. Master’s degree? Check. PhD? Easy. From a nobody to a scientific sensation, he ascends to celebrity status. But as he delves deeper into the system’s missions, he realizes his journey is far from over. Can he achieve the ultimate glory of a Nobel Prize? Blake's quest for knowledge and fame is just beginning, but the system holds secrets that could change humanity forever.

"Twilight" a fictional character came from Role Playing Game called [Tales of the Legion Heroes] He was an overpowered mob character that can surpass the main character in the storyline. One day, Mr. Daisuke died officially on Earth and was reincarnated inside the body of 17 years old "Twilight" Because of an unhealthy lifestyle and bad habits like overworking his body by playing the game to pay the several million of debt from the loan shark. He was given a second chance by the God & Goddess of Asgard and summon to another world similar and at the same time different from the so-called Earth. [AETHER] 'A world that revolved around the main character!' 'If you are thinking that I was just a mob character who has no role in the storyline then you are wrong.' 'Even if I have no role in the storyline doesn't mean that I cannot surpass the main character or the protagonist.' 'I will use my profound knowledge and wisdom to clear the Impossible quest and mission.' 'I will hoard all artifacts and treasure that are found inside the dungeon.' 'I will climb the top step by step and reach the height that humankind never reached before.' 'Lastly, I will support the main character from the shadow and change their shitty ending that destroys this world.' 'I shall let the world know my name [Twilight] The Dominator, who will soon become the living legend of Nine World Realm.' 'Just hearing my name brings justice and order to the land while making enemies tremble in fear!' 'Twilight will annihilate all enemies before him!... mark as a true hero of Midgard.'

The world was invaded by monsters that suddenly appeared all over the world and a system-like software had been installed on some humans' intelligence by an unknown force. The war between monsters and humans was bloody and two billion people lost their lives. Jianyu, who was at the bottom of the power ranking of the Upgraded Humans with his team, was preparing for a future where he would lead humanity against this extraordinary enemy...

Andrew Smith, a pro player in the virtual reality game curia online, a game that models a magical world called curia. Andrew Smith and several thousand other players fought the last boss the demon sovereign and lost. No one on earth knew exactly what happened, but those several other thousand players who died in the game, fighting the demon sovereign, never woke up from their virtual capsules. Azraf Skythunder, a young man from an ancient World called Valens, hailing from the Ancient Skythunder clan, an ancient clan that has a glorious history and an age-long mission of protecting all worlds was sent on a mission to prove himself a worthy man who is worth upholding his Ancestors mission. Andrew Smith's and Azraf Skythunder, faith, crossed paths when Andrew smith died in the virtual reality game and when Azraf Skyrhunder died on the mission after slaying the mighty lightning blue dragon. Their souls intertwined and Azraf Skythunder reincarnated into Andrew Smith's modern world. A world that was bizarre in his eyes, was filled with wonders to him but at the same time, a disaster lurked behind the curtains. he could not understand the reason why he was sent into this foreign world, his father had once told him that nothing in this world is a coincidence, so coupled with Andrew Smith's memories, he tries to find out his place and mission in this endangered world.

When two civilizations clash with each other, a college student who was at the very front among his peers in his study experienced something he would never have thought of in his wildest dreams. After his second death, he returned to the place where he should have been but everything was unfamiliar to him. Not to mention, his way of using his new power makes him caught up in war he would never have expected. Would he be able to adapt in the new world or shall he be swallowed by it? And would he be able to uncover the truth of the invasion to his planet and deal with those who wished him harm from the underworld organization?

Willing to work hard and spend all his savings to give his fiancée, Evelyn, a gift she would like on her birthday, Elric was met with a bitter reality. He was betrayed. However, more than that, Evelyn's cold attitude was far more painful than her family's harsh words. When he was cast aside, he suppressed all the anger in his heart until a system of patience and resilience emerged. A system of life endurance. This system forbade him from seeking revenge, but it slowly made him unstoppable. The cowardly Elric was forged into an extraordinary figure who was challenging to defeat.

After rising from the dead, Niff was given an order by the Moon Goddess to free the Land of Amaphera from the cursed magic power of the Dark Shadow. The problem is that Niff lost his strength, got swapped in another man body, and lost all his memory—can't even remember his own name! How will Niff liberate Amaphera Country? How will the search for the six bodies of Amaphera Country's strongest mages hidden by the Dark Shadow succeed? How does Niff unravel the big secrets of Amaphera Country? Niff struggle to get his life back, against fate to fight for his whole life as a half blood witch,, and to change the prophecy of fate will begin when he rises from the dead.

At the tender age of fifteen, a prince was expelled from the splendor of the palace, and his breath ceasing at the age of 31 marked the beginning of an endless journey. His life, akin to a wheel ceaselessly turning, traversed nine cycles of tragic repetitions. Tirelessly, he assumed various roles: from an itinerant trader to a daring Class S adventurer. Yet, his fate felt like a song stuck on repeat: death at the hands of the imperial queen each time he reached the age of 31. However, in his tenth life, the prince devised a new plan. With fervent determination, he resolved to confront the queen who had been the root cause of his tragic deaths. Yet, as he infiltrated the academy where the queen sought knowledge, hidden secrets unveiled before his eyes. Unbeknownst to him, he became entangled in the whirlpool of palace conspiracies and intrigues far beyond his imagination. On the quest for truth, the prince discovered unexpected love, strengthened friendships, and the latent power within himself. As he struggled to break the curse that shackled his life, tough choices emerged before him: would he succumb to the burning desire for revenge, or opt to reshape the continually revolving future? Ultimately, the prince must decide whether he will break free from the chains of his tragic destiny or remain ensnared in the unending circle of life.

Ibuki Ken is a young man that despises society very much. There are many causes why Ibuki dislikes society that much. He hates society because society is so judgmental, apathetic, and ignorant. There are so many stereotypes and stigma. "it’s toxic!" "Society is so fake that the truth hurts people!" Choosing to be single and have no friends, He was as abnormal, immature, sad. That’s was his choice. But Why DOES GOD CHOOSE HIM TO BE REINCARNATED IN ANOTHER WORLD

Harith is a poor college student who is murdered in cold blood by some bandits. Fortunately he's given a second chance and he reincarnated in a magic filled world and with a new name. Determined to not be as useless as he was in his previous life, Harith makes a vow and starts his journey to become the most powerful being ever.