Mare Tranquillitatis

Mare Tranquillitatis (静かの海) is the hidden fourteenth server, located on the Moon. Before the Catastrophe, it was the test server and was referred to as "N_VOEN". After the Catastrophe, it has become the place where Adventurers go before they revive and return to Theldesia.

The Prison of Time is located here.

Overview
During the game era, this server was called "N_VOEN" and was a testing server before expansions were rolled out. Shiroe created his Roe2 alt on this server some time prior to joining the Debauchery Tea Party. Whenever a new expansion is about to be released, N_VOEN is closed off starting around a week before the release. After the Catastrophe, it has become the place where Adventurers go to after being killed.

When Adventurers first get killed, they will find themselves revisiting parts of their memories of the old world. As they wander around, they eventually find themselves on a sandy beach overlooking a body of water, and can see Earth. There, they sacrifice a small part of their memories in order to return home; since the process is instinctive, it is suggested that it is impossible for one to consciously resist it.

Server Information
When Shiroe checks Mare Tranquillitatis' information in The Changing Battlefield, he sees a screen with garbled text. Fans on 2ch deciphered it to reveal some more information about the server.

Trivia

 * Mare Tranquillitatis is a real lunar mare. Its name means "Sea of Tranquility."
 * Volume 5's Interlude states that the Adventurers of Akiba and Minami will one day come together in areas called the "Sky Labyrinth of Imbrium" (インブリウムの空中迷宮) and "Mare Nectaris" (神酒の海). Like Mare Tranquillitatis, Mare Nectaris and Mare Imbrium are also real lunar mares. Why Imbrium does not follow the 'Mare' pattern and why it is written in katakana rather than with its proper Japanese name is as of yet unknown.