The Gloom of the Styx, the Battle Plain of the Lower, Oinos is the first layer of the Grey Waste. It is here that the front lines of the Blood War are drawn and the worst offensives of the Blood War can be found. As scarred by violence as Oinos is, however, it is the diseases spawned by the fields of the dead that best mark the layer in the eyes of others; few can enter Oinos for long without picking up one of the many illnesses that saturate the air and water. Diseases both natural (if distorted by the fiendish energies of the dead) and artificial, formed by virtue of the Oinoloth, the yugoloth ruling the layer from the tremendous heights of Khin-Oin. Those without immunity from disease have a 10% chance each day to contract some deadly disease; most likely the wasting sickness, but any deadly disease could be contracted. Additionally, all saving throws connected to diseases in any fashion receive a -4 penalty while within Oinos, whether or not the disease was contracted on the layer.
Even as compared to other locations that have been touched by the Blood War, Oinos stands as especially hardstruck, as the unique qualities of the plane mean that standard fiendish tactics — scrying on a distant army and teleporting into their midst, retreating en masse through natural teleportation, and the like — cannot function within the Wastes. Instead, armies are forced to enter into Oinos via natural portals or barges upon the Styx and march towards one another as any mortal army would, leaving carnage in their wake, and they are forced to fight to near-complete destruction, unable to easily retreat from one another due to the powerful combat magicks at the command of all those involved. While all Blood War battlefields leave their scars on the land, none are so deep as those within Oinos.
Oinos appears as a nearly flat, grey field, the soil especially gritty and dry; in fact, the top layer of soil in most of the land is no soil at all, but rather the ash that remains from a fiendish corpse after the millennia of decay required to break it down to its core elements. Few plants grow here, and those that do have their growth stunted, as though they can hardly put forth the effort to reach their full height. The occasional jagged, rocky hill breaks through the ground, giving some rare variety to the landscape, but for the most part nothing marks the horizon but the construction of others. The stench of a charnelhouse weighs heavy across the layer, and the sounds of distant clashing of weapons and screams of pain are a constant undercurrent wherever one travels in the open air.
- Manual of the Planes, pp.109-110
- On Hallowed Ground, pp.172-182
- Planes of Conflict - Liber Malevolentiae, pgs.45,49-53
- Planes of Conflict - Player's Guide, pp.28-32