Synopsis
A horror-dice adventure game based on the legend of Cthulu
Similar to TRPGs, the story evolves depending on attributes such as ability, luck and dice rolls.
On an island in the Seto Inland Sea, a cursed protagonist seeks to unravel the mysteries behind the evil god, as well as the legend of the Sky and the Earth to free himself of his curse.
* Please be aware that the background illustrations have been created with generative AI.
Feature to change the main character’s default art
By following the steps below, you can change the protagonist’s appearance.
1. Please follow the requirements below:
[Image basics]
– Size: width 1920 height 1080 pixels
– File type: Background clear PNG file
– Number of images: 11 (Expression variation images)
– File name: Name them similar to the examples below.
tsujo.png
odoroki.png
kyouki.png
hohoemi.png
egao.png
aseri.png
hensou.png
hensou_aseri.png
ikari.png
kanashimi.png
fushin.png
* Hensou is displayed when infiltrating.
Prepare your unique art and enjoy the game.
2. Place your images in the Local game folder
For Windows: Jukashima_Data/StreamingAssets/player
For Mac: Right-click Jukashima.app, See all contents and place the images in Contents/Resources/Data/StreamingAssets/player.
Ability Score
Your ability score is decided by the questions you’ll be asked. Those with a high ability score will be able to enjoy thrilling dice rolls.
Dice roll choices
During important scenes, the success or failure of your decisions are decided by dice rolls.
A high success rate is determined by the ability scores of the protagonist and his friends.
Success will sometimes be guaranteed within a limited time range or during dangerous moments.
Map search
Exploring the map leaves the protagonist hungry and will cause the curse to react, causing the protagonist to have a fit and decrease the success rate when dice-rolling.
It is important to consider your actions before moving.
Story branches
Depending on the protagonist’s state and his relationships with the characters that appear in the story, the latter half of the story will diverge greatly.
Try to complete the endings with all of the characters if you can.
This work was created partially with AI.
| Circle | Gotcha Gotcha Games Inc. |
| Tags | Adventure, Voice, Music, Application, Japanese, English |
| Price | 2,090JPY |
Editorial Review
Horror-flavored dice adventures occupy a narrow corner of the doujin landscape, sitting between the visual novel and the tabletop RPG. Mythos-inspired titles are common, but most reduce the cosmic dread to atmosphere and a linear script. The Isle Of Ubohoth leans into the mechanical side instead. Its story shifts according to ability scores, luck, and dice rolls, the way a Call of Cthulhu-style session would.
The setup is distinctive. A cursed protagonist on an island in the Seto Inland Sea investigates an evil god and a “Sky and the Earth” legend in hopes of breaking his own curse. Moving the Mythos to a Japanese setting is a smart regional twist, and the personal stakes give the dice a reason to matter. The standout feature is the swappable protagonist art. Players can replace the default sprite with their own 1920×1080 transparent PNGs across eleven expression states, including a dedicated disguise image for infiltration scenes. That is unusually thorough customization for an indie adventure, and it fits the tabletop spirit of playing “your” investigator. Voice acting, music, and Japanese and English support round out the package. One caveat: the background illustrations are generative AI, which some players will find a dealbreaker and others will accept as a practical choice for a small production.
Anyone who enjoys TRPG-style randomness, Lovecraftian investigation, and tinkering with their own character art will get the most out of it, especially players who prefer mechanical tension to passive reading.
A flexible, dice-driven Mythos outing whose customization outshines its visuals, and one worth trying if you want your sanity tested by chance.
Official English version available ↓
Get “Cthulu Mythos ADV The Isle Of ” on DLsite
English Version → Free TrialJapanese Original
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Related Tags:
English | Japanese | Application | Music | Adventure
