The supporting character's harem is very normal - Chapter 511: Can you guys just give me a break?

To correct the mistakes of his past, a young man is forced to narrow the space between science and witchcraft, as he ventures on a quest to save his world from complete destruction.

Dying at a young age after a disappointing life. Mat thought he hit the jackpot when he got reincarnated on a tropical island as a baby. Here, exploring mysterious lands and learning magic are a reality. The world of Elydes is beautiful and magical, wild and savage. While the Guide is impartial to all, people are not. Mat has the lowest starting point possible, and those like him rarely go far. To not let his humble birth define his life, he'll need to find the determination to grow stronger and delve into the mysteries of Elydes.

An ordinary youth living in the year 2050 in the Western calendar accidentally came to a fantasy world created by the collision of magical elements and supernatural technology at the other end of the dimension…

- Description from novelbuddy

The cousin that Jing Huan has been closest to since he was a child was labelled as “the other woman” in a certain popular online game: only after devoting herself did she know that the other party was a jerk with a girlfriend.