The Stingiest Boyfriend: The Entire Internet Begged For Me To Break Up - Chapter 44 - Unconcealable Joy

As the last abyssal demon in the world, Wen Long was pulled into various worlds to do tasks by a guy who claimed to be a system. The goal of her mission was to save those villains who had been blackened for various reasons…

- Description from Novelupdates

16 years old-- most boys would be falling in love, as their hormones all rise to unprecedented levels. Most boys at Riley's age would have dreams; dreams that will slowly grow into passion. Riley, however, at age 16... killed the world's number 1 superhero.

Almond Crowshade was the last surviving human in a dying world whose people failed to conquer the Grand Abyss Labyrinth’s 30th floor in time. The world was getting destroyed, and Almond was the last one challenging the 30th Floor multiple times despite the imminent destruction of the planet. He ultimately defeated the Floor Boss on his dying breath by achieving a true awakening, acquiring an X-rank Trait that signified limitless potential. Alas, he won but there was no home or future for what he fought. But a mysterious figure arrived there, feeling pity and amusement. “This is too precious and fun of a toy to let it rot here. You shall reincarnate and climb up to make things interesting.” [Transfer to another world commencing…] [Your memories will be sealed, and you will reincarnate in another world that has welcomed Grimworld’s tutorial like this one. Clearing each floor of the Grand Abyss Labyrinth will unlock a portion of your memories, until the 10th Floor upon which you will gain your full memories.] ‘I’m giving you a second chance. This time, you must clear the Grimworld’s tutorial and step onto the big game to make things instresting and entertaining.’ [Good luck.]

The main character Lei Yu does not have the ability to practice his family’s martial arts. He gets stepped on and tossed around. Due to certain reasons, he leaves the family, coincidentally gains an ability, and makes his own path to becoming an immortal.