This article is for reference purpose
The features described in this article are already implemented in the game. The article should describe how a certain aspect of the game currently works. You may of course edit this article to improve the description of the circumstances. Your opinions or improvement suggestions about the described aspects themself are of course appreciated, too. But please put these on the discussion page of this article to keep facts and fiction separated.
Mirror Lake Protocol (or MLP) is a protocol used for inter-server communication. Its original concept was made by Hocus as a protocol which would permit players from different servers to hang out together and eventually even do quests together.
The current implementation differ from the original specification. This is a non-standard protocol which relies on TMW Vault for authentication ─ made originally to secure TMW rEvolt accounts. If you are playing in ManaPlus, you are not using the Mirror Lake Protocol and cannot use it.
TMW Vault
The Mana World Vault is where your authentication details and mirror lake data are securely stored.
Direct server registration will store your data in plain text and authenticate over TCP/plain, whereas the "Vault" stores it securely in a modern format (PBKDF2) and authenticates over HTTPS. As your personal data is now minimally secure in comparison to direct server registration, the name was chosen to be "Vault".
Mana Launcher
Mana Launcher is a fancy wrapper written in Ren'Py for Steam, which implements the Mirror Lake Protocol and provides some minor features of its own.
Currently, only the Mana Launcher implements the Mirror Lake Protocol.
You can obtain it on the Installation page.
Soul Level and Soul Experience
A cosmetic system to track your progress in all the servers together. Originally designed to provide Steam achievements and to unlock optional cutscenes on Mana Launcher.
Mirror Lake (ingame)
Game Servers may implement special locations ("Mirror Lakes") which allow you to move directly from a server to another. It is not entirely seamless, but much smoother.
Using a Mirror Lake to move between worlds send miscellaneous data which may make you appear in a different position on the target world, including positions which cannot be normally reached from the target world.
Some quests may require you to use specific mirror lakes. For lore purposes, the login portal is also considered a Mirror Lake.
Home World
You can, at any time, select a home world. Once a home world is set, it cannot be changed.
The home world will inform any other world which implements the MLP regarding your overall experience and progress, when you try to log into it. No communication happens unless you decide to visit another world. The guest world will, following a conversion table, import your progress from the home world.
When set, you can spend most of your time on the home world, and do quests on the guest worlds without having to grind excessively to participate. Keep in mind, however, that experience and items acquired on guest worlds will not be sent to the home world.
By default, the experience stack, which means progress on guest worlds tend to be much faster than in the home world. This may make you want to change the home world later, so be careful when deciding on it.
NOTE: Most worlds implement this as an experience bonus. Exact values, however, differ based on worlds, and this feature might not be available in every world.
Staff may, at its sole discretion, allow home world changes, but it normally is disallowed as to prevent cheating.
World Autonomy and Differences
Each world is a full world on its own. It may have slightly different gameplay rules even if they follow a general pattern (given they're all based on the same core engine, all are open source, etc).
The worlds do not need to be controlled by TMW Team, but they'll always have complied with the Privacy Policy and other agreements ─ meaning you do not need to agree with different terms of service. This is to allow for forks, however, as of the time of writing, all forks have joined TMW Team.
No data is sent to other worlds unless you explicitly attempt to connect to them. You can obtain data about them before playing on the upper menu of the Mana Launcher.
Different worlds may, however, have their own rules. In particular, except for Classic, every world disallows multiple accounts.
The Crossroads World
The concept of Crossroad World is a world where you can login with your home world equipment. This is done by using an ID offset. You cannot set the crossroad as your home world. In the cross road, you are theoretically able to trade equipment from different worlds, and join events such as hunting bosses which do threaten the whole multiverse (giving, hopefully, a real feeling of a multiverse endangering situation ─ with multiple worlds sending their best warriors!)
However, at the time of writing, the Crossroad was just a lump of snow floating in æthyr, being used only for Event:Blanc's Trial.