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Sanctum Protocol

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Sanctum Protocol

Koisoft · Published by Koisoft

Content notice: This game contains full nudity and explicit sexual content between adult characters, including sexual acts and suggestive situations involving female characters. It features both consensual and non-consensual sexual scenes, including BDSM elements, and explores themes of religious corruption and manipulation of religious figures (nuns). Some encounters involve fantastical or supernatural beings, which the player may "purify" through sexual interactions. Players sensitive to sexual content, BDSM, non-consensual themes, or morally complex sexual situations should avoid playing this game.

4 user reviews — 100% positive (4 reviews)

Last updated 28 Sept 2026

After the cataclysm known as The Breach, a young civilian awakens the power of the Guardian to purify demons. Fight alongside the warrior nuns or surrender to forbidden pleasure... every choice will shape your corruption and the fate of the world.

DJCTQ 18

£4.29

Lowest price we've ever recorded

View on Steam

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Price history

4 Sept 2026Lowest: £4.29 · Highest: £4.296 Oct 2026

Indie · 2026 · More under £5 games

In Sanctum Protocol, explore post-apocalyptic ruins and make critical decisions that alter your corruption level. Join warrior nuns or succumb to forbidden pleasures in this unique indie experience from Koisoft.

About this game

After the cataclysm known as The Breach, portals opened to a dimension of corrupted pleasure, unleashing demonic entities that shattered the spiritual balance of Earth.

Humanity’s last hope lies with the Order of the White Lance — warrior nuns who combine faith, sacred technology, and combat to contain the corruption.

You are a young civilian who, after an encounter with a succubus, awakens the forbidden power of the Guardian: the ability to purify demons through the body.

The nuns believe you might be the key to salvation... but a mysterious figure watches your every move.

💠 Every choice you make will shape your power, your corruption, and the fate of the world.

🌟 Sacred Path – Fight alongside the Order, purify demons, and strengthen your bonds with the warrior nuns, who take their sacred form.
🌑 Corrupt Path – Surrender to forbidden pleasure, drag the nuns into corruption, and follow Lilith’s call, witnessing their corrupt transformation.

Key Features

  • Adult visual novel with moral, sexual, and spiritual choices leading to multiple endings.

  • Purification System (NSFW): purify demons through pleasure while your own corruption progresses.

  • Explore the Sanctuary and the city: each day you must choose your actions — talk to someone, train, or rest? Your limited energy creates opportunities for replayability to explore different outcomes.

  • Deep relationships with the main nuns: Elysia, Noa, Malina, and Caelia — with romance, betrayal, and mutual corruption routes.

  • Character transformation: depending on the path you choose, the nuns will change their form and personality between sacred or corrupt versions.

  • Dream visions gradually reveal the prophecy and the origin of the Protocolum Sanctum.

  • Dark, provocative anime-style artwork, carefully reviewed and curated for consistency and quality.

System Requirements

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Minimum

Minimum:
  • OS *: Microsoft Windows 7 / 8 / 10 / 11
  • Processor: 1.5Ghz Processor or better
  • Memory: 1 GB RAM
  • Graphics: Integrated Graphics Chip
  • Storage: 3 GB available space

Recommended

Recommended:
  • OS *: Microsoft Windows 7 / 8 / 10 / 11
  • Processor: Pentium 4 or better
  • Memory: 2 GB RAM
  • Graphics: Integrated Graphics Chip
  • Storage: 3 GB available space

Supported Languages

English, Spanish - Latin America

Latest news

  • AnnouncementsOfficial

    Try the Demo for my new Fantasy game!

    Hi everyone! I want to invite you to try the free demo of my upcoming project, a fantasy visual novel that you can already play on Steam.Become the Dungeon Lord!Experience this fantasy visual novel! Defend your dungeon while uncovering the secrets hidden within. Venture outside to explore the world beyond and meet new vassals.👉 Play the Demo & Add to Wishlist here!
    Read full article on Community Announcements (Fox)

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