The fourth stratum is considered by many to be the true world of Pangera. An incredible land of abundant mana, rich resources and verdant forests. Those strong enough to contest with the powerful monsters that spawn here can live an incredible life of infinite possibilities. For this reason, territory on the fourth is desperately sought and fiercely protected. Many of the great powers of the world have established their centre of government in this layer, their surface kingdoms existing merely to funnel people and resources to this, more important battleground.

If one looks deeper, there are multiple reasons for this, but perhaps one of the most overlooked is the nature of the fifth stratum. There is a great deal of focus on the positive qualities of the fourth, but in reality the inhospitable wasteland that is the fifth is a major reason why the fourth is so populated. First, it means an entire stratum is completely unsuitable for habitation, which puts a premium on land within the fourth. Unlike the third, which is merely unpleasant to live in, the fifth is completely hostile to life to an almost absurd degree.

The other consideration, is that the best place in the Dungeon to establish a powerbase to launch expeditions deeper is the fourth. The closer you can establish your safe zone to the fifth, the more likely you are to be able to push through and reach the sixth. For this reason, many consider the fifth stratum, the 'world of decay' to be the great dividing line of the Dungeon, even a halfway marker, of sorts. Of course, it is unknown, at least to this scholar, how many strata there are to the Dungeon, so this is more of an unofficial title than an accurate descriptor, but the sentiment remains a powerful one.

As to what powers and wealth reside in the sixth for those strong enough to reach it, it's a little galling to admit that this humble researcher does not know. Such things are the closest kept secrets of the great powers and any speculation on my part would be purely baseless.

Excerpt from 'The great dividing line: The fifth stratum' by Elric.

Commander Myriam wasn't happy. In an unfortunate quirk of her character, at least in the context of the role she served within the Legion, when she wasn't happy it tended to show clearly on her face. Not the best trait for an ambassador to have, but as long as the consul didn't care, then neither did she.

In truth, the Legionem Abyssi didn't seem to value tact in its representatives. The Legion didn't value pretty words, they valued powerful actions, which was likely why all of their missives to foreign powers were carried exclusively by the immensely powerful.

It was difficult for the faces of the kaarmodo to show strong emotion, but she could tell from their stillness, their unblinking stares, and the defensive posture of the setsulah, that they could feel the anger rolling off her in waves.

Good.

These idiot lizards had spat on thousands of years of tradition and discipline, they had better feel her anger. When she felt she had a good enough grip on her temper, Myriam turned to the ancient creature beside her and looked him dead in the eye.

"Please explain to me, Mahaan," she grated out, "exactly what you expect the Consul to say when I bring her word of this," she gestured roughly to the scene in front of her, "atrocity?"

The Mahaan shifted slightly under her withering glare and the setsulah attendants reacted as if she'd punched the fool in the snoot. She shifted her glare onto them and they froze as the weight of her displeasure fell upon them as a physical weight.

[If you would speak with your mind I would understand you more clearly,] the deep tones of Parron'tep rang in her head, [it is important that we communicate clearly in such trying times.]

The commander grit her teeth once again at the arrogance of the oversized gecko. Who in the hell did he think he was talking to?

"Let me be clear," she bit off each word as she spoke, "if you don't explain this situation to my satisfaction, I will request the Consul intervene personally. I assure you, she will descend on this mountain at the head of our massed Legions and she will flatten it, along with you and everyone else in this room. Then your people will thank her and pray to all they hold dear that she stops there. You are in the coldest possible sand, Mahaan, one wrong word and you will freeze to death."

The clear, naked threat in her words riled the kaarmodo and they reacted strongly. The enormous creatures peeled back their lips to reveal dagger like teeth dripping with venom as the human in their midst threatened their lives with open contempt. All around the room the attendants reached for their weapons, needle pointed teeth bared in anger as their master's indignation boiled across their bond. Despite all of their anger, nobody moved, as Myriam stood in the centre of the room untouched.

She even went as far as to tap her booted foot on the floor impatiently, waiting for a response from the Mahaan. Still, none of the kaarmodo moved. She could not be harmed, of this they were all keenly aware.

[We anticipated that you would not approve of this action,] Parron'tep replied. [As the Mahaan of this clutch, I have taken the responsibility of seeing this plan through to its completion, all that we ask is the Legion leave us to execute on our strategy in peace.]

If it were possible, the commander's face grew even tighter.

"You want us to look aside from a clear breach of everything the Legion has ever stood for? Three thousand years of martial tradition and sacrifice? For what gain?"

[The waves are growing ever stronger and they have not ceased,] the Mahaan replied. [Surely the Legion believes, as we do, that the possibility of a second cataclysm exists? We cannot wait for such an event without taking measures to prepare. If we are able to remove the Mother Tree, it will be a Mythic class monster that the Ancients are not able to convert to their side. Or worse, consume.]

"If you want to kill the Tree then rally your forces, contact your allies and attack it. Why resort to this… abomination?"

[We cannot risk losing even a fraction of our strength if we are to survive another Rending. Would the Legion throw their soldiers away knowing what is to come?]

The commander didn't reply, but it was clear that she did not approve.

"All you do is create another problem, bigger than the one you are trying to solve."

[They are perfectly under control. There is no chance they will escape our containment.]

Myriam snorted.

"That's what everyone thinks, right up until the last possible moment. It will get out of your control, nothing is surer. On the brink of a second cataclysm, this is exactly the sort of thing you shouldn't be doing. You create new enemies for us to fight at a time we are spread far too thin already."

She looked out through the shield once more into the chamber beyond. It was dark inside, but her enhanced vision saw everything in disgusting detail. Three pale, bulbous bodies, each over fifty metres long, pulsed grotesquely as an army of smaller insect-type monsters swarmed around them, hauling away clutches of eggs every second. At the heads of the beasts a constant train of workers came carrying loads of fungus grown in the vast fields beyond the chamber, an endless stream of food for the queens.

It sickened her.

"I already know what the response from the Consul will be. Shut it down, now," she spat.

A pause.

[With respect, commander, we will wait for an official response from your leader before we make a decision.]

"And in the meantime you'll continue as planned?" Myriam growled.

The Mahaan closed his eyes.

[Of course,] he replied.