Abyss is a region of Vesania that lies 8 million light-years from Serenus. It is Vesania's largest region, at 5 million light-years across, and is completely opaque.
It intersects with another universe in such a way that transforms light energy travelling into it into matter, and then back into light on the far side. This matter forms in diffuse clouds, constantly heading out of the region.
Because of this, most races are completely blind within this area. Many unusual and disconcerting phenomena have been reported by those entering, but none have travelled more than 100 light-years in. Automated craft cease working upon entrance.
The particular size and ferocity of these organisms is of note, as well as the unexplained fact that they are rarely seen outside this area. Some scholars believe they travel back into Abyss within a few hours of leaving.