Feeling that he'd spent enough time marveling his newfound power, Hades thought that it was time he inspected his new domain.
For the most part, it was a vast field of red stone. Further out in the distance, he could see a dark cave that gave out a dark, malevolent aura. Around him were human souls, all wailing and shrieking. In the opposite direction of the cave, he could make out a palace made of black and red stone. It gave off a feeling of dread and austerity, of death and destruction. It was very imposing, and Hades found it to be unnerving. After all, it looked like a darker version of the palace on Olympus. He couldn't understand how the original Hades felt it to be a good idea, but it would NOT stand to live in a copy of someone else's home. Not at all.
Beyond the palace he could see the River Styx circling the great black Wall of Erebos marking the boundary of the Underworld proper. He could see all the souls on the opposite shore clamouring to get into the underworld, with Charon ferrying people across. Some distance away, he could see the River Lethe and a small cabin on its shores, a cabin that probably belonged to Hypnos.
Close to the walls he could see the Fields of Asphodel, the Fields of Punishment and Elysium, but with nothing to keep track of them, souls kept wandering from one place to another, some not even reaching any of them at all. Heroes wound up in Punishment, tyrants and monsters landed in Asphodel, regular people broke into Elysium and some ended up nowhere, just wandering around in pain. It was all very chaotic.
According to his memories, the cave was a direct entrance into the realm of Tartarus below ('Gonna have to close that off to everyone immediately'). Also, it seems that he hadn't properly made the Underworld into humanity's afterlife yet. At this point, Prometheus had yet to steal the coals from the central hearth on Olypmus yet, so they were all barbarians at this point. As a result, he hadn't cared about the wailing human souls enough to do something about it yet.
The other Gods looked down on humanity, but not Hades. Hades knew how important humanity would become to the Gods later on. Sustaining their existence, fighting their battles, becoming Gods in their own right if they were demigods; humans would grow to become a vital part to all of society, mortal and immortal. They would inhabit all land on the face of the Earth and with merely their thoughts and ideas, completely changed the Gods themselves, giving rise to the Greek/Roman personality disorder all the Gods suffered from. Not to mention the colossal smackdowns that were to come (*cough* Titans *cough* Giants *cough* Primordials *cough*).
Basically, his house was an edge lord's wet dream, he had to completely build everything in the Underworld and, given all the other Gods' fear of him, he'd have to do it himself.
"Great. Just great. I know I shouldn't complain, but why do I have to do this? Why couldn't it have already been made?"
Rising from the throne he had found himself in, he made his way over to his palace. From up close, it gave off a sense of power and dominance. Sure, the colour scheme was a little dark, but everything else seemed fine.
Opening the gates, he made his way through the palace. He inspected the rooms and the hallways, assessed the capabilities of his skeleton servants and studied the artwork and architecture of his new home. Most of it, to his surprise, was quite pleasing to look at. Not at all the doom and gloom he was expecting. With great haste, he made his way to his throne room.
'The rest of the palace can be focused on later, but it is a must that my throne room is perfect.'
After some time, hecame to a very large set of double doors around 12 metres in height made of sleek ebony, built to be able to grant passage to Gods and Titans quite comfortably. Upon entering, he came into what could only be a necromancer's evil lair. The whole scheme was black and gloomy, with depictions of death and torture along the walls. Atop a flight of black steps was a towering throne made completely out of bones, decorated with skulls all along it. It radiated a deathly aura and felt as familiar to him as his spear and helm.
Hades grimaced.
'No. My throne room will not look like this. Not at all. The throne room is meant to make someone look kingly, not evil! Why would I ever agree to this!?'
With a wave of his hand, he removed all that could be removed, leaving only the bare stone and windows. Without all the other ornaments and decorations, it did not seem too bad for a throne room, discounting the throne.
As far as he recalled, spring had just started on the surface, meaning it was currently March. So he had about 9 months to redecorate his throne room in a manner that pleased him.
So for 9 months, he laboured in the throne room. He refused the help of his servants when they offered. He had an image in mind and he wanted to personally bring it to fruition, and he knew that it would be too much of a hassle if others were to build it as they wouldnt understand what he was going for.
The Furies expressed their confusion and asked if they could help him in any way. They took offense to the fact that the King of the Underworld was personally building his own throne room. After much discussion, they relented on the condition that Hades would tell them everything he needed and that they would personally bring it for him. Given that he could just summon ores as he wished, he sent them out to collect specific types of stone to use for the floors, walls and pillars.
With 4 months to spare, Hades stepped back and marveled at his work. He had basically recreated the entirety of the Nazarick throne room from Overlord. He knew that, as a god, it was unbecoming of him to base his throne room around an anime, but he recognised that the design was one very well suited to what he was looking for.
A wide, high room, enough for several hundred people, with a high ceiling and surrounding walls that were predominantly white, with golden decorations as highlights depicting the war against the Titans and the landscape of the Underworld.
Hanging from the ceiling were numerous chandeliers made of precious stones of all colors of the rainbow, and emitted a fantastic, dreamlike radiance. Numerous flags emblazoned with the symbol he had taken for himself, a black helm with flaming eyes on a red field, hung from flagpoles embedded into the walls.
In the center the room was a flight of stairs about 10 steps high. Atop these stairs was a gigantic throne, carved out of a single piece of black and red crystal, whose back was high enough to touch the ceiling above it. A huge red banner hung down behind it, proudly displaying Hades' symbol.
Looking at his finished work, he felt proud looking at his new throne room. The only thing that bothered him was that his symbol was everywhere, making seem in bad taste. What he needed was variety in the flags ('Maybe if I get other gods to reside here under my rule...'), but for now it was fine.
Now that everything to do with the palace was complete, it was time for him to look outwards. He didnt know how Hades had done it originally, but he didn't want his domain to be filled with nothing but monsters and dead people. Yes, the dead would still come to the underworld, but he wanted to make a civilisation down here. At least make a few cities. Then his throne room would actually have significance.
Beyond the underworld, everything was still relatively simple. The humans didn't have fire yet, so no God was looking in their direction. This meant that now was the best time to make the mortals have a favourable impression of him before interacting with the other Gods.
The Fates weren't born that long ago, which meant that it was still very early on and Zeus had just ended his relationship with his second wife Themis after birthing the three Fates. He also knew that Demeter had bot been raped yet at this time, so his original future wife Persephone hadn't been born yet. Haephestus, Ares, Athena, Artemis, Apollo, Hermes and Dionysis weren't born yet either. He wasn't sure if Aphrodite had formed from Ouranus' ichor yet. However useful 'Percy Jackson's Greek Gods' was in hindsight, there was no way for him to remember everything.
Hephaestus could be a possible ally on Olympus. Dionysis, Aphrodite and Ares would be useless in that regard, looking out only for themselves and their own enjoyment. The others were an unknown for now. He wouldnt be able to tell until he interacted with them.
Beyond even the Gods were the other pantheons. Given that it stated 'Riordanverse' when he was reincarnating here, that meant the Egyptian and Asgardian gods were real too. Not only that, but all the other pantheons too, if the Egyptian God of Knowledge Thoth is to be believed. That meant God politics and conflicts with Asgard, Egypt, Heaven, possibly the Jade Emperor and his court in the east, the Aztec gods, the various tribal gods, the Shinto Shrine and all the other thousands of gods and pantheons. The strongest of them could be separated into 5, including Olympus: Olympus, Asgard, Egypt, Heaven(Abrahamic) and Heaven(Chinese). North, South, East, West and Centre. These are the superpowers among the divine pantheons. How all the creation myths fitted in to all of this would require more research, but that is how things stood currently.
The best way to combat the other pantheons would be to weaken their religious base. Hades would need to figure out how and why, but the Gods were tied to the faith their worshippers had in them. This particular tactic wouldn't work on the Chinese Gods ('Need to figure out the secrets of their cultivation'), but it should definitely work against the others.
If he increased the size of his domain, he should be able to have enough space to develop a civilisation, but the only way to do that would be to either wait patiently for more souls to come in or to expand his territory via invading Tartarus. He innately knew that, due to making a primordial's divine authority and power his own, he should be able to take that of another. So taking territory in Tartarus would expand the Underworld, making him more powerful. It would also weaken Tartarus, weakening the Giants and minsters he would birth later to oppose the Gods. He'd be killing three birds with one stone.
But that was a thought for another day. His concern now was the upcoming winter solstice.