Free Communication Game
Ouroboros 4


Termination of O4 service

O4 service has been terminated. An archived version intended for esteemed long-time users is available on, yet the data is not reflected in the latest version. Also, this version does not have the ability to enter the 3D world. (See other ouroboros services.)

Video archive released

A part of the past archive of videos, distributed on media including Twitter, has been released on Youtube.

How Google prevents invalid traffic

Our specialists carefully monitor clicks and impressions on Google ads in order to protect your interests as well as those of our advertisers. To do this, we use both automated systems and human reviews, analyzing all ad clicks and impressions for any invalid traffic that may artificially drive up an advertiser's costs or a publisher's earnings. In addition to our automated system, we have a team dedicated to detecting invalid traffic using several specialized tools and a wide variety of techniques based on extensive experience tracking and monitoring user behavior and analyzing scenarios. We continually upgrade our detection mechanisms to proactively combat invalid traffic.

Twitter official account

The link to the official Twitter account is as follows.

Mobile device support status

Mobile device support is in progress, but some are operational. The full screen button is automatically displayed in the upper right corner of window when you use a device that supports full screen mode. However, 30-inch (1600 pixels tall) or larger screen is required to view the market, the colosseum and the tavern.

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Notice of the ouroboros launge update

Please check the status of the site in the lounge during site maintenance or in the event of a failure.

Go to the lounge

Amazon Authentication

You can only use one Amazon account to sign in. You can create multiple character data on one Amazon account.
Check Amazon Help for account management. (password change, two-step verification settings, identity verification, etc.) Conditions of UsePrivacy Notice

When purchasing on Amazon, please use the link below.

For newcomers

OUROBOROS is one of the "metaverses" aimed at making many friends in the process of growing a character. You can exchange various items such as weapons, shields and armor with other players, or get funds to build a house wherever you like. You can also create a town or country by increasing the number of friends. We are currently working on an upgrade from a previous Adobe Flash version, but you can play it. If you have any opinions or impressions, they will be reflected in the game system, so please post them on the bulletin board or chat.

more about the Ouroboros World

Image: Ouroboros

the Ouroboros World


The world of Ouroboros consists of 15 towering columnar continents. Continents are connected by a tunnel that passes through a different dimensional space called a gate. You are free to build houses and towns on the map of the continent.

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Image: Ouroboros4


Each square on the map has a 3D space. Inside, you can camp, fight and explore.

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Image: Ouroboros4


Once you get used to this game, exploring the dungeon is an attractive place. There is a super powerful monster in the deepest part of the dungeon, but if you win it, you will get valuable treasures. The size of the dungeon varies. The dungeon with multiple floors has stairs. The first goal is to reach the stairs and move on to the next floor. To get deeper into the dungeon where the sun light doesn't come in, you need to turn on the torch or the lantern. Please note that the light will gradually diminish over time, and it goes out.

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Image: Ouroboros4


When you encounter an enemy, the battle takes place in a circular field. Once the battle begins, the battle is automatic and no action is required. Before starting the battle, you can adjust the placement and behavior of your soldiers so that you can win efficiently .

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Image: Ouroboros4

Item Composition

By synthesizing items, you can create new powerful items. In the kitchen, you can make cuisine items using ingredient items.

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Image: Ouroboros4


This game is under development, but it is stable as an open world. We are developing by listening to a wide range of opinions from visitors. In the past, it has been built using Adobe Flash technology, and so far we have been migrating to HTML Living Standard. In the future, we plan to realize a gimmick that utilizes HTML Living Standard technology in earnest. Chrome browser for development environment I use it, but basically it supports all major browsers such as Edge and Firefox.

Technical cooperation: matenro, github repositories