Gods proving grounds/beyond the veil - Lore

Within pockets of aberrant earth, there are gateways to some ineffable place, perhaps a collection of places. These are unlike the simulacrums present in long-abandoned human dwellings with some level of familiarity amongst the terrifying visages nor the alien worlds that one might visit with the use of a Tera portal . These locations are completely alien, not from this earth or space, as if the reservoir from which the aberrance on earth feeds out. Few organizations and governments know of the happenings beyond these places if they could even be understood. To reach these places requires venturing into the most demonic of Arks, and even so, The few passages into these places are short-lived and indistinguishable from a naturally occurring Tera portal.  The only glimpse of what might lie beyond the veil is from the crazed ramblings of Cultists and the stoic riddles of the most exalted of pilgrims that have ventured into such places. Of the many individuals within these groups, both terrorists and shamen alike, their stories are often similar. Of the terrain, description varies but is often a quizzical picture of an absent horizon and an endless sky in a variety of colors. Of the weather, the description also varies, often calm, often chaotic with a heavy thick atmosphere. Of flora and fauna, the description is usually the same. Subjects describe a perpetual metamorphosis, as creatures and plants or in constant change, as their forms shift from familiar creatures and the next moment form into pulsing masses to once more change to some viable but alien design. This all occurring in a matter of minutes. Further, some have trouble describing much of anything, many explaining that it would be like describing colors to someone that can't see. 
The tenants of many cultist organizations around the earth have come to describe these places as "gods proving grounds" where all of creation tests their "designs" before bringing them to earth. Gods proving grounds have thus become the moniker to distinguish these locations from haunts where some vestiges of the "real" world are still present. Despite the lack of understanding of what these locations are, both researchers and the general human population agree that the occurrences on earth, including the natural disasters, haunts, and abominations  are likely a result of some unseen parallel reaction between the proving grounds, and earth, and possibly further.