The Voidsea
Plane of Reality
Black, Dark Blue
Gravity
Universal
'One of the earliest records we have of the Voidsea refer to it as 'Outer Space'. As far as names go, it's appropriate, I suppose - They thought of 'Space' as being 'outside' their worlds, but the truth is the opposite - We are always within it. Our worlds are but islands within the Voidsea.' - Captain Abyss-Breach, 17th Century of the Valhallan Age
The Voidsea, formerly known as Outer Space, and many other names, is one of the two overlapping realties which exist in the Valhallan Age. Of the two, the Voidsea is by far, the larger, but is made up primarily of empty space. It is one of the primary frontiers of the Eternal War of Ideology.
It's defining feature is the vast, uninhabitable distances between Void Islands, Void Coves, and other celestial bodies, requiring the use of advanced technology, biological engineering, or other such adaptations for many lifeforms to travel between worlds while in this reality. In contrast to it's counterpart, the Realmlands, this expanse is often compared to an endless ocean of nothing, hence the name, Voidsea.
As a matter of understanding, the Voidsea refers to the entire reality itself - anything within it is a part of it - The Sky River and all it's satellite Gyres, the Void Islands, Shoals, and Void Archipelago's are all part of the Voidsea.
The Voidsea is distinct from the Realmlands in a number of other ways - Technology that does not work in the Realmlands works within the Voidsea, for example. While a starship might work in the Voidsea, that exact same starship would not work in the Realmlands. The reason for this is not exactly clear. However, unlike the Realmlands, the distances needed to travel from world to world is massive, by factors of thousands, tens of thousands, or even millions, depending on the two worlds in question.
The discovery of the Realmlands originally lead many across the Sky River to believe that the Voidsea was to become an almost irreverent frontier in terms of travel, conflict, and colonization. This was the exact opposite of what would end up becoming the case - Rather, the Voidsea became one of the two fronts within the Eternal War of Ideology, requiring just as much focus on on a strategic and military level. Battles are fought for any world within reach, and some Factions go to great lengths to hide their Prescence on some worlds, in order to hide technological developments, Taekni training centres, deployments, or launch-points for additional attacks.