Tensei Shitara Slime Datta Ken (WN) - Prologue

This is the tale of an earthling, who transmigrated as a dying third-rate god but somehow rose through the ranks, gaining followers and eventually causing the Fourth Great Apocalypse.

A life filled with regrets.Once he realized his faults and decided to lead a new life, it was too late.His family was already gone.He had borne through each day with pure rage.Finally at the end of his misery, his wish reached the heavens—an unforgiven one.He goes against fate to raise his sword.

At 18, Alex Kain is whisked away to Eryndor, a game-like realm where he gains 'Skill Synthesis', a talent to fuse skills into godlike powers. Battling monsters and conquering dungeons, he builds a harem of strong women drawn to his might and charm. With the power to return to Earth bearing incredible resources, Alex faces a growing threat that endangers both worlds in this epic of adventure, romance, and ambition.

The Queen of the elves wants to bear his child, the vatican’s saintess is his maid and the empire’s princess wants to elope with him.

But his only concern was his delusion of taking down the creator of the world!

- Description from Novelupdates