The Gray Waste of Hades, located at the midpoint of the Lower Planes, is was a plane of evil balanced between Law and Chaos
The three layers of Hades are called glooms for good reason; they are realms devoid of emotion, hope, and peace. Gray land and gray sky throughout, with no sun, moon or seasons to break the monotony. Any color other than shades of gray would be obvious against the background but would fade to gray in a week or two. And like bright colors, beings would begin to fade also. At first they would feel the drain of emotions leaving only sadness, ennui, and defeatism. In a tenday or two they would be trapped in Hades and their existence would begin to fade until finally they became larvae.
Marble obelisks, about 1,000 feet high and carved with indecipherable runes taller than a man's height. At least three of those obelisks are known to exist (one on each layer), but there may be more. They all look extraordinarily ancient, even by planar standards.
Once in a while, the runes will start glowing red. When that happens, whoever is standing near will be subjected to crushing sadness and despair, making it much harder for them to keep resisting the influence of the Waste.
But sometimes, the runes will start glowing blue. And when that happens, whoever is standing near will feel a burst of energy. That effect is powerful enough to restore will and purpose to those people who've been affected by the Waste.
This is a city which exists in all of the layers of Hades simultaneously. Those staying here are immune to the will-draining effect that affects them in most of Hades. It is the largest trading center in the Gray Wastes.
There is a portal from a former soup kitchen in the Hive (destroyed during the Slimy Doom Plague)to the Oinas section of the City. The key is any piece of gray slate stained with a drop of fresh blood.
The Oinos sector is arid and dry, with ramshackle buildings. Only the poorest live here. The sector is subject to the disease that ravages Oinos (though it's much less virulent here). Consequently, it's isolated from the rest of the city by walls. People who want to leave it have to spend a day in quarantine.
The Niflheim sector feels more like a pioneer town and its inhabitants are middle-class (craftsmen, shopkeepers…). Everything here is made of wood. The main market is found here, as well as many taverns and inns. This is a place of honest labor, but it can be quite rough : when somebody doesn't like somebody else, he's not likely to be subtle or reasonable about it.
The Pluton sector is as of yet unexplored by the Party.
Oinas is the first layer of Hades. The Party exited a portal from the Hive area of Sigil into the Oinas area of The City in the Center. Its main inhabitants seemed to be diseased beggars. It is city policy that travelers who wish to enter the rest of the city must pass a day in quarantine first.
The second layer of Hades. The terrain here consists of foothills, with cooler temperatures, healthier vegetation including pine trees, and no disease. Everything is cloaked in dreary fog and mist, limiting vision to about a hundred feet (thirty meters).
Nifleheim is home to numerous pillars which give off positive or negative energy randomly, at random times. The pillars are often used as places to conduct foul rituals, such as the one the party encountered near Death of Innocence. (32)
Nifleheim can be reached by way of The World Tree, Yggdrasil. At its roots is Náströnd, the realm of Nidhogg, the worm that gnaws at the bottom of Yssdrgil. One day he will gnaw all the way through, and then Ragnarok will start.
Nastrond is mostly composed of a large underground lake, with an island on it. On the island is Nidhogg, and a feasthouse where it lives, as well as a root from the tree Yssdrgil. There is a Ferryman living on the shore of the lake who will ferry passangers from the Yssdrgil side to the tunnels for gems or magical items. Beyond the lake are some tunnels. Walking into the wind leads to Niffleheim, and walking with the wind leads to Loki's realm in Pandemonium.
The Party travelled through Nastrond on their way to fight Jeb and the Blades of Hel. (32).
Death of Innocence was a town halfway between The City in the Center and The World Tree, Yggdrasil. Like the City in the Center, people who stayed here were immune to Hades' will draining effects. Viliki Cainor, a human fighter, was the mayor of the town. She had founded the town approximately three years before the party visited, with a group of slaves that she had rescued.
The town was attacked by Jeb and the Blades of Hel a while back, and managed to fend them off after massive losses, according to a planeswalker named Kherion.
Thompson (or Terrence, or Thomas), a woodcutter who had gotten captured and kept in a pit at the Blades of Hel camp before the party freed him, is from this town. So is the Half-Elf, Kherion Mallibrun, who the party rescued from a ritual being conducted by a Blood Fiend near a fallen pillar in Hades.
The Party rescued a third person from Death of Innocence, named Jacobs. Jacobs had been out with Thompson when he was captured, but had run and hidden in a cave that turned out to be the hiding place of Kherion Mallibrun's sacrificial altar, where he sacrificed Yugoloths in order to keep the town safe using the Ritual of Appeasement.
After the Planeswalkers hunted him down and confronted him about it, he begged them not to tell the rest of the townsfolk, feeling it would destroy their hope. The Party agreed, and helped him escape secretly to Sigil.
The rest of the town was convinced to vacate to the area surrounding the Army in Ysgard, where a new town, Birth of Hope, was founded by Viliki.
(32).
The Blades of Hel were among those who attacked the Army in Ysgard while the party was dealing with the Ship of Chaos in the Abyss (28). They live at the base of The World Tree, Yggdrasil, by the mouth of the cave that leads to Hel's realm.
They have a tattoo of Hel's face split by a sword on their left breast. They know that they are doomed to go to Hel's realm for being cowards or sneaks, but they feel wronged by the world. They sometimes disguise themselves and sneak into the camps of warriors, to stab them in their sleep and deny them a hero's death.
Reinhalt saw Jeb training some of them when he scryed on Jeb after the attack on the camp(31). They also attacked the Death of Innocence (town, see above) with Jeb.
The Party assaulted the Blades camp and killed most of them, along with Jeb, putting an end to one threat to the Army. They found that the Cleric who had been leading them (along with Jeb) was not dedicated to Hel, but was actually worshipping the Shadow Lord. (32)