The Selestat Anomaly

In a valley west of Selestat in the Massif Des Vosges the headwaters of a river starts. It flows down supplying Selestat with fresh water. Also, it brings trouble at times, along with potential benefits for local mages. As an area it is referred to as the Selestat Anomaly. The Franks are constantly at war here against the Saxons who are hiding in the local region and being supplied & helped by locals. Part of the difficulty of removing the Saxons is this Anomaly. Cold mists hang around the valley regularly spilling out of a source tucked away at the top. These mists seem to gradually move down & disperse over the river, yet at the same time magic energy seems to pass into the water and surrounding lands. This leads to it being easier to cast spells of any kind, yet also has a rather nasty side-effect. Mutations, still-births, and malevolent energies also show up too.
Many small settlements near the valley report glimpsing many different shapes, shadows and entities appearing. Some of these settlements have disappeared, or at least the inhabitants have, sometimes with signs of absolute carnage being left behind. Strange markings, languages, glyphs & other carvings are found all up through the valley to the gorge. Many creatures that have travelled up have reported the feeling of being watched. Strange sounds and cold spots can be felt too especially higher up one goes. What surprises many is that there is both plants & animals still living up high here though not in great number for the latter. It seems only the hardiest animals exist one goes up, and many trails, made by both animals and travellers are also found.
A few brave souls have made it to the end and found the source of the mist, headwaters and what appears to be a portal. Carved out of the rock surrounding it, cold almost sentient mist flows out at different heights, sometimes barely visible, sometimes enough to completely obscuring the terrain. It sits near the edge of a twenty foot drop down to the river's headwaters, a path leads up either side to it, allowing one roughly human sized creature to pass along it, with barely any room to move. Loose stone & gravel are present on it making it slow going, getting worse from late Autumn to early Spring when rainwater, ice, snow, and winds add an extra problem.
The actual portal shows snakes circling a rectangular hole of absolute darkness. Many of these snakes seem to be biting down on the tails of others, and each corner has an Ouroboros carved on top of it. To activate the portal a spell such as Dimension Door or similar, or getting a glass flute and playing a few specific notes that causes the Ouroboros symbols to unravel. This latter method seems well-known in surrounding settlements though they cannot fathom how they know that information. On top of that, no-one seems to work out what the notes are. If activated by either method, it opens a the portal proper, mist forms in the space, but the exact dimension it leads to could be any, and seems to last until the end of the next full moon. A story that is attributed to this is that only places of eternal darkness rests on the other side, and only the most wise of individuals would survive on the other side. The Ouroboros designs position after the portal is opened seems to indicate which dimension or world has been opened. For many this would indicate that there is a possibility that somewhere in the world someone knows it, or at least recorded it in some fashion.

Type

Valley