Mythos: Book One is an adult visual novel by Nine of Swords, built in Ren'Py with 3D CG art. It is a supernatural murder mystery comedy set in a fictional version of the real world. You play as a customizable main character, either male or female, who learns that their ex-girlfriend, Lisa Harrison, has died under strange circumstances. The story follows the character as they stumble into a hidden society of supernatural beings, some matching legends and others surprising. Players make choices to solve the mystery, and romance routes may be single, group-based, or abstinent, mixing fantasy, humor, and harem themes.
The current build is v1.1.0.0, released July 27, 2025. Book One is presented as a complete story, with ongoing updates. It runs on Windows, Mac, Linux, and Android, with English and French language support, and it is uncensored. The latest changelog adds a French translation, fixes bugs, and corrects minor typos. Earlier full-story notes describe discovering secret supernatural societies, eating questionable diner food, and petting a cat.
Developer's description
A Supernatural Murder Mystery Comedy!
Mythos is an adult visual novel game set in a fictitious version of our world. You follow the story of the main character – which you may choose to be male or female – as they learn of the mysterious death of their ex-girlfriend. Soon, the main character finds themself fumbling through the hidden society of supernatural beings that lurk in plain sight. Some of them are very much like the legends suggest, while others couldn’t be further from what one would expect.
Will our hero piece together the puzzle behind the murder of Lisa Harrison, or will they be consumed by new attention they’ve brought upon themselves?
Mythos will feature multiple choices to solve the mystery, and relationship paths that can be monogamous, harem-based, or even
celibate
(if that’s the kind of kinky thing you’re in to).
Trailer
Spoiler
v1.1.0.0
French translation
Bugfixes and minor typo corrections
2025-04-04 - v1.0.0.2
Tales from Mythos screen fixed
2025-03-20 - v1.0.0.0
Mythos, Book One is now a full story. Solve the mystery of Lisa Harrison's death! Discover the supernatural world and secret societies that have lurked just below the surface. Eat some really questionable diner food. Pet a cat.
Seriously, pet the cat. What's wrong with you?
I proudly present my complete game - hopefully the first of many!
2023-12-24: Chapter 5.0.1 Hotfix
There's a bug in chapter 5.0.0 where if you make a particular choice (kissing Lisa) your character name will be reset to default (Kylie or Kyle depending on your gender).
If you use the default name, anyway, this won't affect you. If keeping your custom name is important, use this hotfixed version.
2023-12-22: Chapter 5.0.0
Chapter Five of the story
New music
Two new achievements
Maybe more cat?
2023-7-28: Chapter 4.1.0
Fixed an issue where Mara would vanish randomly
Fixed an issue where some people experienced hanging during transitions
Fixed an issue where the Android version was just broken as fuck
2023-7-26: Chapter 4.0.1
Chapter Four of the story
New music
One new Tales from Mythos
Three new achievements
More cat
2022-11-18: Chapter 3.11
Investigation Mod Assistance added
2022-10-31: Chapter 3.0.0
Chapter 3 of the story
Improved menu selection
New opening animation
New music
Text box opacity slider
Tales from Mythos - short stories included in the game client unlocked at certain points in the story
Investigation mode - click on text and it may reveal more clues
Relationship walkthrough (enable in preferences)
2021-10-02: Chapter 2.0.4
All this does is add the new side images, which
should
2021-09-10: Chapter 2.0
Chapter 2 of the story (13 Scenes)
Added a "Hide Text Box" option to the Quick Menu for Android builds
New Title Screen
31 new BGM tracks
New characters (suspects?) introduced
5 new achievements
New fonts for character nameplates
2021-03-05: Chapter 1.1
Bugfix
2021-02-23: Chapter 1.1
Bugfixes and fixing typos
2021-02-16: Chapter 1.0
Chapter 1 Full
2021-02-15
Chapter One Preview
Player reviews
Player rating4.5 / 5 · 20 ratings
Written reviews20 · avg 3.9★
Positive (4–5★)60%
Latest review2025-10-30
What players say
Many players praise the story and characters, while others criticize humor, romance, and adult content.
5★10
4★2
3★4
2★3
1★1
Players like
Engaging mystery story with strong writing and plot twists.
Well-written characters with clear, distinct personalities.
Humor and playful dialogue keep the tone light.
Choices and gender selection add some replay value.
Common complaints
Limited adult content feels tacked on or low priority.
Early humor can feel forced, exhausting, or overdone.
Romance and character development feel rushed or shallow.
Best for players who like story-heavy mystery, humor, and character-focused adult games.
Summarised from 20 written player reviews.
whatmi2025-10-30★★★★★
This game is basic nothing and i really expected 5 stars experience Pros: game works well and its easy to play actual criminal magic case girls looks different from each other Cons: Not enough sex for that many girls when…
radiells2025-10-18★★★★★
"Adult" value of the game is rather low, but I found plot genuinely interesting. With supernatural, mystery murder and all of this. I also really liked that game has built-in hints about available clues and romantic paths. Regarding negatives, I…
JRotiart2025-09-12★★★★★
This game presents a surprisingly entertaining story, with a strong emphasis on lore and world-building. Normally, that level of exposition can bog a game down, but here it’s handled with a lighthearted touch. Humor, playful dialogue, and even a sprinkle…
★★★★★(20)
