MTL - Genius Fundamentals - Chapter 182 until

I exist in the darkness, disappear under the bright light, and will eventually devour the sun and turn into the shadow of all things… Known by people as the indescribable terror of darkness; the king of shadows; the dark day; the existence of the shadow of the world , is still just a somewhat special high school student, facing a weird death game…

- Description from novelbuddy

Falling in love with my imposter sister's fiance wasn't the plan. After finding out that she was exchanged at birth and was the real daughter of the Moore family, Eliana was expecting a turn in her life, but nothing changed except that she lived in a big house and could now eat good food. Her parents still ignored her and everything good was first given to Amber, their imposter daughter.She was twelve when she met him, when he saved her from drowning, and when she found out that he already had a betrothed. It was already known that the eldest son of the Sanders family was betrothed to the eldest daughter of the Moore family since birth. She knew this, and it was only natural that she accepted this, but the more they crossed paths, the more she wanted him and the more she wanted more for herself. Eliana was ready to do anything to achieve all her dark desires, even if it made her a villain.After all, there is a saying that goes “Villians are not born, they are made.”

Takahiro Nao, a 25-year-old burdened by crushing debt and driven solely by his love for his struggling family, meets a tragic end—until a mysterious Goddess of Benevolence offers him a second chance: reincarnated in another world, and his efforts there will provide for his family back on Earth. Awakening in the body of Naoki von Blackmore, a disgraced “Failed Hero,” Nao is thrust into a realm of sword and magic, monsters, and war, tasked with the impossible mission of defeating the Demon King. With newfound powers, a shadowy past, and the weight of two worlds on his shoulders, he must battle not only relentless enemies but fate itself. Blending emotional depth, thrilling action, moments of humor, and a spark of romance, this gripping isekai adventure asks: how far would you go—and what would you sacrifice—for the people you love?