Deep in the dungeons below Oolacile, it would seem that the townsfolk tortured various humans. Broken-through cells can be found with chains dangling from the ceiling. One such tortured soul is found at the entrance of it, who seems to have been mounted and chained to a pole.
A primeval serpent convinced the people of Oolacile to open the grave of the primeval man, likely initiated by Kaathe with the hopes of setting in motion the prophecy of the Dark Lord.
Or perhaps by Frampt, attempting to harvest the power of the Dark Soul in a desperate act to to prolong the Age of Fire.
Hawkeye Gough Dialogue:
Dark of the Abyss, which swallowed poor Artorias, threatens to devour our entire land of Oolacile.
It seems that this dire fate is unavoidable.
But, seduced by a Dark serpent or no,
They awoke that thing themselves, and drove it mad.
…One's demise is always one's own making.
If thine wish is to succeed poor Artorias, and challenge the spread of the Dark,
Then thou must face Manus, Father of the Abyss.
The Dark emanates from Manus himself.
Even if this land shall expire, thou may be able to prevent further corrosion.
Elizabeth Dialogue:
Thy Scent is very human, indeed.
…But, not intolerable…
But Princess Dusk is here no longer…
…snatched away by that horrifying primeval human.
Marvellous Chester Dialogue:
Believe it or not…
Oolacile has brought the Abyss upon itself.
Fooled by that toothy serpent, they upturned the grave of primeval man, and incited his ornery wrath.
What could they have been thinking?
According to Gough and Marvellous Chester, Oolacile was tricked by a primeval serpent. It is possible that the Kalameet theory played a part in this, thus the folk of Oolacile began to search for a new means of power to protect themselves from the dragon. In their quest for power, they discovered an ancient burial ground where they awoke and tortured the primeval human that lay there, to the brink of madness.
It is possible that to discover these powerful, dark sorceries they tortured various humans, and that the sorcerer may have been human as well, but the likelihood of one of these sorcerers becoming Manus is unlikely. Furthermore, note tyhat it is known that there were various other human being tortured by Oolacile, yet none of them created such a catastrophy.
Dark Fog
Abyss sorcery discovered by an Oolacile sorcerer on the brink of madness.
Although Dark Fog is, in theory, relatively close to humanity, it also happens to be a terrible poison for humans.
Perhaps it reflects man's cruelty against his own.
It seems that they not only tortured him, but also took his pendant, setting him over the edge, transforming him into Manus, Father of the Abyss. This is supported by:
Soul of Manus
Soul of Manus, Father of the Abyss.
This extraordinary soul is a viscous, lukewarm lump of gentle humanity.
Ancient Manus was clearly once human.
But he became the Father of the Abyss after his humanity went wild, eternally seeking his precious broken pendant.
Dusk of Oolacile Dialogue:
I still think on that creature from the Abyss that preyed upon me.
My faculties were far from lucid, but I quite clearly sensed certain emotions.
A wrenching nostalgia, a lost joy, an object of obsession, and a sincere hope to reclaim it…
Could these thoughts belong to the beast from the Abyss?
But if that were true, then perhaps it is no beast after all?
Pursuers:
Sorcery of Manus, Father of the Abyss.
Grant a fleeting will to the Dark of humanity, and volley the result.
The will feels envy, or perhaps love, and despite the inevitably trite and tragic ending,
the will sees no alternative, and is driven madly toward its target.
Manus, driven mad, attacked everything around him. His humanity and power gone rampant, created a spreading Abyss, that began consuming all of Oolacile, transforming and corrupting all in its path, in his rage and attempt to find his precious broken pendant.
Kaathe gives the only information about the furtive pygmy:
After the advent of fire, the ancient lords found the three souls.
But your progenitor found a fourth, unique soul.
The Dark Soul.
Your ancestor claimed the Dark Soul and waited for Fire to subside.
And soon, the flames did fade, and only Dark remained.
Thus began the age of men, the Age of Dark.
Last but not least, note how Manus' soul is described to be a lukewarm lump of gently humanity and that his humanity went wild. Looking at his soul icon, a humanity sprite can be seen amidst the chaotic growths on his soul.
The stones circling Manus grave are reminiscent of Stonehenge, it is a clearly marked burial site and it seems particularly important. As it is known, humanity is central to the influence of the furtive pymgy - humanity sprites are found within the Oolacile dungeons.
During the Game no Shokutaku interview with Miyazaki, he said:
The image is something like a human ancestor. It found the Lord Soul and humanity is like a fragment of it. Kinda like an ancestor, so the descendants have a part of that soul
