Second Chapter notes: I'm gonna skip most of the LoZ timeline, but state how Demise and such ended up forming in this story. I'm going to be skipping from there to the important points then. I do not own Dark Souls, Legend of Zelda, and Typemoonverse. As for what armor Berosus wore, he wore elite knight armor in dark souls 1, and then Fallen knight armor in Dark souls 3.
When Berosus had fallen into dust, there was also another black, inky substance stuck to his armor, and began gathering up the dust. The armor then picked itself back together and the dust began to form a black scaled body within the armor which now had a black, cold, aura around it. The armor stood up and looked at its hand, and then formed a fist before walking towards a cave, menacing glowing red eyes showing. This...was the beginning of Demise, who had been born from Dark Soul that Berosus had held, along with the much larger Dark Soul that Gael had. The Embers that had left the body was actually Berosus himself and Filianor's consciousness and souls, well for Berosus it was the soul he had accidentally made for himself when he continued to gather so many of the light souls of hollows and such he killed, along with linking with the fire once, in a twisted sense, Demise was his Dark half given form.
Demise took advantage of the age of dark and began experimenting and crafting his dark armies, as well as making a dark alternate realm to use as to avoid pissing off the coming Type that was bound to be made when the embers begin finally showing up. Demise wanted to ensure he was ready to kill his other half and his mate for daring to reject him. Centuries passed and this hate continued to grow, especially when the goddesses made their appearance and ended the age of dark, though they had to fight him to truly end it, in the end, they banished him into the very dark realm he had created using their immeasurable power, which only fueled his hatred all the more. He was the Demon King, and so when he returned a century later and encountered Filianor's godlike reincarnation known as Hylia, a long war started, and ended when he got damaged badly by the reincarnation of Berosus, though not before he managed to gut the damned hero, but before he could recover from the battle, Hylia sealed him away, and then had herself reincarnate as a mortal centuries later.
The Reincarnation of Berosus' name, was Link. The reason Gaia didn't interfere was that it trusted Link and Hylia to put Demise down before he does too much damage. Then Demise put his curse on Link and Zelda's spirits in which his hatred would rise again and again. This hatred would reincarnate into Ganondorf, and when thousands of years later, the hatred and evil became powerful enough to become a calamity, to which it did so by absorbing energy from all the world's evils committed. The hate of Demise, had eventually become known as...All the world's evils. Legend states that a boy was made a sacrifice in which to take in all the worlds evils into, this tragic sacrifice ended up taking in even the hate of Demise.
The magical Hyrule would become hidden under and illusion on Antarctica and would be sought after by Magus's everywhere, only to fail every time. The reason for this is because Hyrule holds the Tri-Force, to which it is understandable as to why the Magus society would wish to find the place, not that they ever would. Surprisingly, Gaia and Alaya actually work together on keeping Hyrule Secret, mainly due to how it is the only area of the world in which Humanity, magic, and nature work in harmony and both entities have no wish to allow the magus's to ruin it, especially as Hyrule's sacred realm holds the very root of the world and is the only place in the world where the age of Gods still remains. As Hyrule is blocked off by powerful illusions and bounded fields, the Magus society had to resort to a different method to attempt to reach Akasha, Heaven's Feel ritual.
This is a ritual that is kept top secret, so as to keep a certain reincarnating hero from ever learning of it. Of course, he would upon the fourth grail war, especially since it would be here that he would find what he had been desperately seeking since the lonely reincarnations had begun.
A lone figure stands on a rooftop, watching the streets below. He wore a green cloak that covered some rather high tech armor that he himself had made enhanced with prana. He wore a helmet that covered his entire face and changed his voice. He also had lots, and lots of weapons on him, all of which he could get from a single pocket in an instant. This was a man that had a hammerspace pocket of sorts and knew how to use it, even if the pocket in question still had limits. He pushed a button on his gauntlet and was suddenly no longer visible. The fabled Green Phantom was now in Fuyuki city, but he had no command seals at all, as the grail never chose him, not that he cares, as he finally found the secret those foolish magus's have been keeping from him, though they probably should've figured this would happen considering he detected the signal 3 times already, and the tracking is what took so long.
Short Chapter I know, can't wait to see the reviews though. As I said in the previous chapter, this is an idea that has been floating around in my head for the longest time, I think you can guess who the 'green phantom' is, as for what happened to Zelda, well...I'll leave you guys to guess. The next chapter will hold a challenge depending on if you can guess what's going on with Zelda right, if you get it right, ready yourselves for a challenge holding a similar set of rules to what this fic is about.