It sounds like you’re referring to a web novel or light novel title, possibly something like — and you’re looking for a Google search result or a full blog post discussing it.
While not exact, this Japanese light novel (and its manga) features a protagonist who ends up surrounded by demons, including a demon lord who falls for him. No explicit “vow,” but the harem elements are strong. eng he who vowed to create a demon harem new google full
Elian's project, once a solitary endeavor, began to attract attention. Fellow writers, artists, and even gamers became interested in his world, seeing its potential as a collaborative, multimedia experience. The idea of a demon harem, once a niche fascination, had blossomed into a shared universe. No explicit “vow,” but the harem elements are strong
In the realm of the internet, where information flows like a boundless river, there lived a man named Elian. He was an engineer by profession, with a heart that beat to the rhythm of coding and innovation. However, Elian harbored a secret ambition, one that diverged sharply from his daylight persona. Under the cloak of night, he nurtured a dream that was as peculiar as it was captivating—to create a demon harem. The idea of a demon harem, once a
He is generally decisive and often manipulative or dominant, which fits the "demon harem" theme, but might not appeal to readers looking for a virtuous protagonist. 3. Pacing and World-Building
: It features an adventure-driven plot where old enemies must learn to work together against broader threats. Where to Play