Weapon Master - Chapter 20

In the middle of a deserted island, a small boy wakes up with two sets of memories: one from his few years of life and the other from a man who lived to adulthood and achieved great things. When he least expected it, a powerful master appeared on the island and took him in as a disciple, revealing a shocking fact: magic exists in that world, and, thanks to it, humanity managed to conquer the galaxy.

A very sweet entertainment circle novel about a closeted gong x fudanshi shou.

- Description from Novelupdates

The strongest hero of humanity, Kim Sung Bin.

After forming a blood pact with the Saint and Demon ladies, the good-for-nothing young boy obtained the Yin-Yang divine veins, learned the art of alchemy and martial arts, and dominated the world.The young Shen Xiang had a romantic encounter with a goddess and a witch, and obtained their supreme inheritance, acquired a divine vein that defied the heavens, learned peerless magical skills, and mastered superb alchemy techniques, which made him very successful on the road of martial arts... When he was hungry, he would refine some pills as snacks, when he was lonely, he would flirt with the high and mighty goddess, when he was bored, he would play with those martial arts masters who came to ask for pills, and when he was tired, he would let the delicate wives around him give him massages...