He Who Vowed to Create a Demon Harem is an adult-oriented RPG developed by Avantgarde and published by

The game centers on the evolving relationships between Theo and his former enemies: : A human soldier driven by the goal of liberating Manc. The Halfas Daughters

1. As his power grew, the Heavens took notice. An army of "Heroes" was dispatched to "rescue" Kaelen from his "captors." Standing before the gates of his new empire, Kaelen drew his blade, but his demon companions stood before him.

   In this series, the protagonist gains power by becoming a “slave” to female demon-fighters. While he doesn’t vow to create a harem, the demon girls do form a harem around him. It’s available in full English scanlation.

   : It features an adventure-driven plot where old enemies must learn to work together against broader threats. Where to Play

   Avantgarde

   " appears to be a niche adult-oriented RPG or visual novel rather than a standard light novel. It is developed by and has gained visibility through gameplay showcases and digital storefronts. Core Premise and Plot

   World-Hopping

   : Some versions of this trope involve a protagonist jumping through different dimensions or "worlds" to increase their power and expand their influence.