My awareness was increasing with every passing nanosecond. Ever since I had first set foot here I had wanted to begin to understand this layer of the Heart of Darkness in the same way that I understood so many other worlds, and now I was beginning to be able to do so. 

With my ever-increasing perception and awareness I began to target every single creature who wandered this layer. Thousands, perhaps millions of creatures, all at once. I didn't hesitate and I willed them to freeze, utilizing a number of my stranger powers to force them to oblige my desires. And a split second after that, before I officially made my choice, I began to project a display of my actions to the inhabitants of this layer. I wanted them to witness something historic: the revival of the demon lords. 

"Inhabitants of the Blackened Boscage... You are witnessing history!" I said, as I placed a hand on the enormous heart of Agustino, all that remained of the first of my true foes to have tasted my wrath in full. I didn't doubt that soon there would be others who met an equally gruesome fate. I smiled gently as I fell to my knees and began to speak reverentially. 

"Heart of Darkness... Blackened Boscage... Accept this offering. Accept this gift and allow me to become the first demon lord since the end of the Mythic Age." I said, while closing my eyes and informing the notification that had popped into view earlier that I was willing to give the layer the heart of Agustino. I heard the ground open up beneath the heart, and I felt the heart begin to fall, slowly, into the hole that had just begun to exist underneath it. As the heart fell a new notification appeared in my mind's eye. 

As the notification entered my view I felt power begin to surge into me. A tidal wave of powers, ones unlike any that I had possessed before, seeped into my soul. And I began to laugh as the powers infused me with all sorts of new abilities.

I read through the notification and chuckled. The strongest demon lord in the history of this universe ruled over just twelve layers? I could match that. That said, now had come the time for me to truly embrace the portfolio of deific concerns I had established myself as being fascinated by. 

When the notification appeared, I chuckled at its length. It was a table, one of the rarer sorts of notifications I had received from time to time. In glancing at it I learned fascinating things about myself, with one new fact being quite an interesting thing that I'd need to investigate later. 

It only took me a moment to fill it out, and when I was done I had a smile on my face. One that radiated newfound power and wickedness. The finished table painted a fascinating picture.

When I had begun filling out the table I had done so with a specific image in mind. In order for demon lords to advance in power they needed to be worshiped by mortals, and they needed to conquer layers of the Heart of Darkness. In time I planned to conquer every single layer, aside from an incredibly small handful I wanted to be run by servants of mine like Sombra. And for the mortal cults who worshiped me as a demon lord, I wanted to be an accessible, easily understood demon lord to follow. 

I was determined to become an approachable demon lord that people could easily follow. In order to do that I had chosen domains and subdomains that would be easy to understand and that went well together. I kept the basic concept of the Shadowy Lord of the Unseen intact, since most of my followers who were going to worship me as a demon lord at the moment were demons, but I also added easily understood aspects to my image as a demon lord. 

As the Shadowy Lord of the Unseen, I was worshipped as a demon-lord-to-be who had powers over darkness, destruction, undeath, and evil. As The Hungering Void, my worship could be seen as easy to understand. I could be worshipped by the hungry, and by gluttons alike. Hedonists and voyeurs would be able to worship me, as would artists and those who dwelled underground or who were so deep underwater that light couldn't reach them.

I wanted to be worshiped by those who were addicted to various sins and depravities, mortals with tastes my powers could easily appeal to. I wanted to be worshiped by those who dwelt underground and those who hated the sun. I would give the leaders of such societies more power and in return, they would turn towards me and lead their subjects in prayers to the Hungering Void.

When I captured the hearts of the rich I would lead them to splurge their wealth on enormous quantities of food and when they ate those foods they would grow decadent and corrupt. When their people starved I would relieve them of the pains of their hunger and when they turned to me I would instantly provide them with actual relief from hunger in the form of abundant harvests. And that was only if I focused on gluttony, the newest of the sins I had chosen to take under my control.  As a god and demon lord of the perverted and of the slothful, my powers had just grown considerably. 

While I was still on my knees near where the heart of Agustino sank into the Blackened Boscage another notification lit up my mind's eye. And it was one of many I was going to receive today that brought a smile to my face.

I felt power surging into me, infusing every centimeter of my body and seeping into my soul. My mind was expanding faster than ever before, and at the moment I felt positively invincible. I laughed and the sound echoed around me, as the very layer itself began to laugh alongside me, mimicking my elated mood. 

I wanted to test my powers, in and out of the Heart of Darkness. I could feel and hear the heartbeat of every single creature in this layer. I could sense the life-force that filled them. 

The next set of notifications were doubled up. One of them alerted me that I had just acquired the second tiers of influence over the domains of war and physics, and the other one was a special alert that informed me of the powers I received as a consequence of gaining power over the sins of gluttony and wrath. And both of those notifications were exhaustive. I was quite the fan of both notifications, as both of them filled me with far more power than I had possessed even a few minutes ago.

Lucianowrites

As a reminder: the difference in power between the Great Old Ones and the Outer Gods in this story is not necessarily something that is evident in Lovecraft's writings or In the works of other contributors to the Cthulhu Mythos. I have it here because it's easier for readers to understand, and it's a common convention in other works that have takes on the Mythos, most notably Pathfinder which has the exact same convention, saying that Great Old Ones are creatures at the level of demigods and that Outer Gods are at the level of "true deities".

For the curious: Graz'zt, one of the big three demon lords of the Abyss in D&D ruled over three layers of the Abyss and his collective holdings were known as "Azzagrat", though even with the power that came with ruling three layers of the Abyss he was still weaker than Demogorgon, the 'Prince of Demons', and D&D's biggest, strongest demon-lord.

And for the Pathfinder friends, the strongest demon-lord is undoubtedly Lamashtu, the mother of madness, one of two demon lords to undergo apotheosis and become a true deity (with the other being Nocticula, the former demon lord of lust, darkness, and assassins who is currently the deity of artists, exiles, and midnight). Lamashtu ruled over a layer of Pathfinder's Abyss named "Kurnugia" which is later than entire planets and is the largest layer of the Abyss that has presently been discussed in Pathfinder materials to date.