I am that male friend in the harem story - Chapter 247: The Noise

Lingyun, a fierce and savage cultivation genius takes over a dead teenager’s body. Coincidentally, they are both named Lingyun. Set in a alternate version of the 21st century, teenager Lingyun has been killed by someone with a grudge.

- Description from Novelupdates

"Magic is believing in yourself, if you can do that, you can make anything happen."

Ikaris, a genius student admired, exploited, and hated all his life for his brilliance, suddenly finds himself transmigrated into The Forsaken Lands, a fantasy world of myriad species born with the ability to use magic with imagination as their only limit.

Alas, this gift carries a curse. The more you use it, the closer you are to death.

After thousands of years of decline, the Free Races are fast approaching their demise, their survival threatened by this curse and an enemy that will not rest until it has devoured them all. Literally.

Former allies and enemies, prey and predators are now cornered behind a huge wall, forced to collaborate to resist their invader. But can so much resentment and hatred be washed away so easily? Can predators and prey really overcome their instincts in the face of a common foe?

Follow him on his journey from an ordinary human to a shining existence that will overturn the order established since the dawn of time. From an innocent soul to a merciless demon. From a human to something else.

Xia Changge is a timid and honest cultivator who has practiced for thirty years without even killing a chicken.

His ordinary life changed after he was killed because his fellow Daoist next door went out to seek opportunities, and begged Xia Changge to help take care of his wife and daughter…

Longevity flow, independent family flow.

- Description from novelbuddy

Having lived a normal life all his life and died without being able to fulfill his desire and when he’s given a task by a god, watch how he takes the protagonists girls while making it hard for the hero.