MTL - I Am Invincible After Awakening the Superman Gene - ~ A New Year's letter to book friends

One week. If you survive, you choose a Cosmic Power... you survive. Jace isn’t one to give up. Not when his sister dies. Not when he loses his legs. And definitely not when The Cosmic System takes over Earth. With nothing more than his street smarts, the clothes on his back, and a river otter companion; he must survive a planet full of vicious predators that see him as an easy meal. If he can survive? He gets to choose a Cosmic Power and a Class. A path to ascension. A way to bring his sister back.

After dying in an oddly anticlimactic vending machine accident, Kazuki Ren is reincarnated in the demon realm—not as a hero, not as a villain, but as the only human male student enrolled at the mysterious Academy of Ruin, a school where all the professors are demon lords and all the students are powerful, beautiful she-demons.Ren is told he has one task: survive.But there’s a catch. The Academy’s darkest secret is about to awaken, and Ren holds a hidden power that could either destroy the demon world... or rule it.Now surrounded by seductive demons with hidden motives, eldritch tomes, forbidden dungeons, and twisted exams, Ren must master his ability—or be consumed.Magic, mystery, danger, and temptation await in this dark academia harem fantasy.

After a young lonely orphan boy died on earth, He was reborn as the Prince of the Everhart Kingdom in Melux. And in this life, he got everything he ever longed for: Luxuries that he didn't have, magic that he only read and fantasized about, different types of sweets that he didn't even know about but most importantly, he finally had a family!He was pleased with his new life as he had parents who despite being the King and Queen of a Kingdom always managed to spend time with him and His maid who would do anything at his words. He could experience the joy of sharing a dinner with family, getting angry over silly things, and then apologizing while bawling his eyes out. He finally felt like he was not alone in this universe anymore and he also had people who cared and loved him dearly. His second life was seemingly perfect in his eyes until that horrifying and gut-wrenching night that flipped his entire world......

“Jiang Yu transmigrates into a novel and becomes a side character in the book.