The supporting character's harem is very normal - Chapter 39 You are also afraid of the Church, right?

As the number one pill alchemist of the immortal world, Mu Chen had always believed that it was because he had single-mindedly focused on concocting pills that led to him to neglect disciplining his disciple. Which in turn, caused his disciple to be led astray by the seduction of devil cultivation, leading to the three realms to fall to disaster. After his rebirth, Mu Chen resolved to properly teach his disciple, give him the very best resources, earnestly love him, carry him close to his heart, teach him by way of example, and didn’t let him grow corrupt.

Sure enough, his disciple became more and more “intimate”. Every day his disciple even crawled into his bed, rubbing against his chest and clinging to his thigh. It was just that his expression isn’t exactly quite right……

- Description from novelupdates

The antique market that is filled with treasures and trash.

Lucius was a man born to a pair of lowly servants that worked for the Great Demon worshiping Barrom clan. Growing up in the harsh conditions of the Barrom clan where magic and power reigned supreme, he weathered though humiliation and schemes. Knowing that he wanted to be the oppressor than the oppressed, he began his conquest. Not averse to betraying or scheming, Lucius made use of his allies as mere pawns to be sacrificed.

Learning that a powerful artifact lost eons ago was hidden in an ancient ruin, Lucius betrayed and sacrificed one of his closest people, his lover without hesitation.

But he didn’t know that fate had a different plan for him and the artifact he had yearned for would send his soul hurtling across the cosmos, forcing it into the broken body of a young man called Asher Inanis. Coming to his senses he finds the world to be completely different where the magic of his previous world did not exist, but what did was ‘Gifts’.

Witness how he learns about the world, gains power and reigns supreme against all odds becoming the Demonic Sage.

Ukei Kaito fought a desperate struggle in order to fulfill his role as a summoned hero. He defeated the Demon Lord and saved the very world, only to meet an end filled but with betrayal. The companions that he’d trusted throughout his journey betrayed him and killed him by sticking a blade through his chest.