Toaru Majutsu no Index: New Testament - Volume 10, Chapter 15: V.S. “The Merciless Scientific Vanguard” Round_07.

Su Heng had traversed to a world where demons were resurrecting, and the human realm was like hell.Water ghosts, fog demons, and drought monsters... powerful demons plagued the land. Major clans used fierce spirits for medicine, residing high above the clouds, while common folk struggled desperately amidst a divine, eerie apocalypse.In these chaotic times, Su Heng awoke with the talent of a Celestial Eater.His body grew limitlessly, gaining a property point for every pound he gained in weight.The bizarre and terrifying demons who slaughtered cities and eradicated nations were, to him, the most sweet and superior ingredients.He devoured their flesh and blood, feasted on their sinews and bones, plundered their Divine Skills, and seized their destinies.From the “Pure Yang Skill” to the “Heavenly Demon Transformation Technique,” from the “Golden Bell Guard” to the “Demon Buddha's Golden Body,” even the most ordinary martial arts in Su Heng's hands could burst forth incredible power.Years later...Su Heng's demonic body was colossal, his weight immeasurable.With a hundred hearts and a thousand arms, mortals were nothing more than ants to him — all gods and buddhas of the heavens, come to battle!

This is a story about the protagonist getting the system, going crazy in the biochemical apocalypse, producing aircraft and tanks, destroying zombies, saving good people and killing bad people.

- Description from novelbuddy

Unable to control his mouth, Lin Jian Yin scared away eight previous girlfriends and six previous managers thanks to his poisonous words. Finally unable to stand it, he goes to a strange antique shop recommended by his friend. The shop supposedly has something that can help him.

Even though a Nintendo that plays cartridges is a bit outdated, and probably no one plays it anymore, isn’t it too exaggerated to place it in an antique shop to sell?

After returning home with a Nintendo, Lin Jian Yin inserts the cartridge that the owner sold to him at a huge discount. Only then does he discover that this is actually a simulation game. The female protagonist isn’t a cute loli, nor is she a mature woman. Rather, with her old lady hair and blue-white slippers, she is such a frightening woman that calling her a Taiwanese babe would seriously be insulting Taiwanese babes.

Gods! His mission is actually to help this woman marry a perfect prince! How is that possible!!!

Wait, as the main guy protagonist, Lin Jian Yin actually isn’t the prince. Then, then, who exactly is he… No, “what” exactly is he?

Jiang Su transmigrated.

He transmigrated into a BL harem novel as the novel’s main character, jianghu’s number one beauty, who bewitches the masses with just his face, then is subjected to shame, humiliation, and infamy at the end.

To prevent this from happening, Jiang Su diligently practiced his swordsmanship. But then he suddenly realized…If he is still single when the original storyline ends, he will be forced to return to his original world.

Jiang Su: ……

- Description from Novelupdates