Mysteria ~Occult Shadows~
Released Sep 2020
Explore the land of Sulnas as the "Shadow of Death", a cat girl who's dauntless and fierce. The land is poisoned by secret power and desperately needs salvation. Can you save it from its sure demise or will you doom its fate like everyone else would?
64% positive · 3,463 reviews
Done
All announced content has been released
High confidence
Done
All announced content has been released
High confidence
Where to buy
Steam $12.99
Can't confirm — worth a look
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Evaluation
Mysteria ~Occult Shadows~ launched into Early Access in August 2019 and officially released as version 1.0 on September 29, 2020. At launch, the developer (producer FinalUnrealityCat) stated the game had a complete story with 14 levels and 6–10 hours of playtime, and expressed that the team intended to move on to new, smaller projects going forward.
The developer's own words at launch described the game as the fullest extent of what they could build with their resources, and made clear they were shifting focus to future titles rather than continuing to develop Mysteria. All 11 DLC items — primarily free costume and soundtrack packs — have been released, with the last batch shipping on October 6, 2020, shortly after the 1.0 release.
A significant note from a June 2024 announcement confirms that the developer no longer owns the intellectual property rights to Mysteria, having moved on to an entirely new self-owned project called "Rebellion GODSOUL." A June 2025 post reiterated this, with the team saying "although we no longer own this IP, we sincerely thank you for your past support." These statements make it clear the developer has no further involvement in Mysteria's development.
There has been no post-launch content beyond the DLC costume packs released in October 2020, no roadmap for future updates, and no indication from the developer of any planned content. The game launched as a complete, finished product and has remained that way since. The completion date aligns with the 1.0 release on September 29, 2020.
Evidence
Developer again confirmed they no longer own the Mysteria IP, framing the post as a farewell message to fans with a commissioned wallpaper as a parting gift.
Developer confirmed they no longer hold the IP rights to Mysteria, and that their new game Rebellion GODSOUL is fully self-owned. This confirms no further Mysteria development is possible from the original creators.
Content
11 of 11 released · no outstanding content
Media
Details
Developer
Publisher
U-Secret Studio
Achievements
39
Platform
Windows
Controller
partial support
Steam Deck
Unsupported
Players
Single-player
About this game
Developed by indie group
"U-Secret Studio"
Kemomimi x Alternate Myth Style
3D Hack&Slash Game
Cute maid, gorgeous Kimono, sexy lingerie, foxy JK.
And all kinds of weapon skins, all free!
The current version of the game is EA 4.0.
It now has a complete story, and would take you about 6-10 hours to get through.
If you encountered any bug, please contact uhome@u-secret.net with screenshots.
We'll send you solutions, complete savedata and original wallpaper for compensation.
--------welcome to mysteria！----------
Guide Death Shadow through a world of wonders.
The world Sulnas is heavily infested with dark power.
Give yourself to the basic instincts and purge this world with light.
+◇ Snappy Controls, challenging in every way. Gets harder as the game progresses.
+◇ Quick Time Events! End your enemies with style.
+◇ Fully animated cut scenes and full Japanese VA.
+◇ Destroy your enemies with 3 kind of weapons
+◇ Well-designed combat system, make every cut deep to your enemies’ flesh and bone.
+◇ Grapple and jump, handle every battle as agile as a cat.
+◇ Puzzles and myths can tell a story on their own.
+◇ Over 40 unique enemies
+◇ 14 Levels! 10 Maps!
+◇ Full controller support
+◇ Fantastic Lighting + Stylized PBR rendering makes the game as real as your fantasies.
+◇ BGMs and music composed by the famous group project lights
+◇ Unique costumes and weapons!
+◇ Fully customized your own experience.
+◇ Customizable cut scenes: Try out our new portrait mode!
Explore the forbidden zones in the mainland, Surnas, discover the biggest secret hidden behind the Ferre civilization, or beat the evil creatures as you wish - you drive the power from the deepest darkness, and nothing constrains you.
《Mysteria: Occult Shadows》is a 3D, free-camera, real-time action adventure game developed by indie game studio formed by College students. This game features the Dark-Tale-Style scenes and Ferre characters design, with a variety of supernatural elements organized into the main and branch stories.
Q&A
Q：How to backup/delete the whole savedata?
A：The whole savedata is a .mss file under C:\Users\{Your User Name}\AppData\Local\Mysteria\Saved
Q：Why the frame rate in the ring like map is especially lower than others?
A：The system will load maps when in that map, the frame rate now depends on the I/O speed of your drive. If you stand still the frame rate will get higher.
"U-Secret Studio"
Kemomimi x Alternate Myth Style
3D Hack&Slash Game
Free Outfits!
10+ outfits, all available in FREE DLCs or in gameCute maid, gorgeous Kimono, sexy lingerie, foxy JK.
And all kinds of weapon skins, all free!
The current version of the game is EA 4.0.
It now has a complete story, and would take you about 6-10 hours to get through.
If you encountered any bug, please contact uhome@u-secret.net with screenshots.
We'll send you solutions, complete savedata and original wallpaper for compensation.
--------welcome to mysteria！----------
Guide Death Shadow through a world of wonders.
The world Sulnas is heavily infested with dark power.
Give yourself to the basic instincts and purge this world with light.
+◇ Snappy Controls, challenging in every way. Gets harder as the game progresses.
+◇ Quick Time Events! End your enemies with style.
+◇ Fully animated cut scenes and full Japanese VA.
+◇ Destroy your enemies with 3 kind of weapons
+◇ Well-designed combat system, make every cut deep to your enemies’ flesh and bone.
+◇ Grapple and jump, handle every battle as agile as a cat.
+◇ Puzzles and myths can tell a story on their own.
+◇ Over 40 unique enemies
+◇ 14 Levels! 10 Maps!
+◇ Full controller support
+◇ Fantastic Lighting + Stylized PBR rendering makes the game as real as your fantasies.
+◇ BGMs and music composed by the famous group project lights
+◇ Unique costumes and weapons!
+◇ Fully customized your own experience.
+◇ Customizable cut scenes: Try out our new portrait mode!
Explore the forbidden zones in the mainland, Surnas, discover the biggest secret hidden behind the Ferre civilization, or beat the evil creatures as you wish - you drive the power from the deepest darkness, and nothing constrains you.
《Mysteria: Occult Shadows》is a 3D, free-camera, real-time action adventure game developed by indie game studio formed by College students. This game features the Dark-Tale-Style scenes and Ferre characters design, with a variety of supernatural elements organized into the main and branch stories.
Q&A
Q：How to backup/delete the whole savedata?
A：The whole savedata is a .mss file under C:\Users\{Your User Name}\AppData\Local\Mysteria\Saved
Q：Why the frame rate in the ring like map is especially lower than others?
A：The system will load maps when in that map, the frame rate now depends on the I/O speed of your drive. If you stand still the frame rate will get higher.
Are these done yet?
Last evaluated Jun 25, 2026
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