Any brief details on the main characters (like the "Gatekeepers") or the specific "Another World" they inhabit?

If you can provide a bit more context, I can help you draft a summary, character analysis, or review.

Where did you read or see this (e.g., a specific fan-translation site, a self-publishing platform like Pixiv or DLsite)?

The title suggests a specific niche—likely a , self-published manga (doujinshi) , or a fan-fiction project—given the use of "NTR" (a common trope in adult or drama-heavy fiction) and the "Another World" (Isekai) setting.