Old Ancestor: Thrown Out By The Nanny From The Start - Chapter 86 - Energy Cannon

Gojo Satoru's cousin, Kiryu, has gotten himself in a dilemna; A Harem that consists of Mei Mei, Utahime, Shoko, and all JJK babes that aren't schoolgirls.

A human warrior cultivating the Ancient Strengthening Technique has transcended dimensions and arrived on Kyushu. Together with twelve ravishing beauties with looks that were unmatched in their generation, will he be able to stand on the summit of this world?

It begins on the mountain.

With the glint of a knife, a flash of steel in the hands of a sworn brother. A betrayal.

Stabbed and pushed down the mountain, Zi Chen lied within the red-stained snow, left to die.

This is where it begins; he is given life by lightning,
baptized by thunder.

Those who had once betrayed him should all suffer in his cruel revenge.

- Description from Novelupdates

This book is about Jay (ceo of Mariano Enterprises) and Keifer (ceo of Watson Enterprises) falling in love. Ofc Jayfer is the endgame :)