The Plot against the Gods. Havel, Velka, Dragons, and the First Born Son
For purposes of brevity, the First Born Son, (i.e. Gwyn's son) will be referred to as FBS or the FBS. I will also presume the FBS is the same person as the Nameless King.
I also presume that much of what Hawkshaw theorizes about the plot against the gods is true, and I credit him with a lot of the assumptions I'm working with.
The Nature of the Departure of the FBS
The FBS leaves Lordran after Gwyn links the Flame. Following his departure, his statues are destroyed and his shrines dismantled, yet his followers remain active. His cult is suppressed, not abandoned. Moreover, the FBS himself continues to watch over his followers, implying he never truly abandoned Lordran.
This does not look like a peaceful departure. It suggests the FBS was removed by a force strong enough to defeat him and politically powerful enough to erase him from history.
Gwyn's departure
The war with the dragons and demons has recently ended. Humanity has been brought into Gwyn’s order, and the Four Kings effectively serve as powerful administrators of the human world.
Gwyn departs to link the Flame. He understands the danger involved, having already seen the Witch of Izalith fail at a similar undertaking. Presumably hoping to survive the process, Gwyn splits his soul beforehand so the linking will not completely consume him.
Crucially, Gwyn does not entrust his son with his soul.
Instead, he distributes fragments of his power among Seath, the Four Kings, and even the Four Knights, something stated by Ornstein’s ds1 soul description.
Ornstein
The DS3 Leo Ring states that Ornstein was the FBS’s first knight, likely meaning his foremost or most trusted knight. Ornstein and the FBS share strong thematic links: lightning-infused spears and dragon hunting. Their relationship likely predates Ornstein’s induction into Gwyn’s Four Knights.
The Four Knights appear to have been assembled gradually, with various candidates accepted or rejected over time. Ornstein likely established his own reputation before Gwyn elevated him.
So what happens when Gwyn names Ornstein one of his personal knights, grants him a ring, and gives Ornstein, rather than his own son, a fragment of his soul? It looks less like a reward and more like a political maneuver. Gwyn is attempting to redirect Ornstein’s loyalty away from the FBS and toward himself.
Gough
Gough is the leader of the Dragonslayers, possesses a unique medallion from Gwyn himself, maintains ties with the giants, and is arguably the strongest of the Four Knights. Above all, he is fiercely loyal to Gwyn. Even after Gwyn is long gone, when he talks to the chosen undead he wishes them Lord Gwyn's blessing.
If Gwyn’s soul fragments are meant to stabilize the kingdom during his absence, then Gwyn’s loyalists become critically important, and Gough is fiercely loyal, and certainly the army of giants and Anor Londo would have his back.
Gwyn's Political Strategy
Why split up his soul at all?
If Gwyn successfully links the Flame and returns alive, he would not want any single individual holding enough concentrated power to threaten him. If the FBS received Gwyn's soul, or even a portion of it, he could potentially overthrow the existing order. Even if Gwyn did nothing, the FBS, a war veteran and hero who would be next in line for the throne, could conceivably displace Gwyn.
The fear of a son supplanting his father is a classic mythological theme, especially within divine dynasties. To plan against this, Gwyn splits his power between multiple powers, keeping it away from his son without compromising the status quo.
Seath is politically isolated, and the Four Kings are mere administrators. But Gwyn has the loyalty of the Black Knights, along with the Four Knights, especially Gough. With their help, Gwyn would overpower them individually even if they hold a portion of his power.
Gwyn deliberately creates a balance of power designed to prevent his son from succeeding him uncontested.
The Plot is Hatched
Gwyn leaves to link the Flame and never returns.
The FBS becomes king in name, but Gwyn’s political order remains intact through the web of loyalties and power-sharing Gwyn established beforehand. The FBS inherits the throne, but does not become the patriarch of the pantheon.
At this point, the FBS begins conspiring with Velka.
I believe Velka is Gwyn’s wife and that Gwyn exploited her, just as he exploited those around him. Velka’s obsession with sin begins with Gwyn’s “first sin”: extending the Age of Fire at the expense of humanity. If you disagree, I will not elaborate at this moment.
The FBS, denied both his father’s soul and his rightful inheritance, conspires with his mother to overthrow Gwyn’s established order and claim his place as ruler of a new age.
I also believe Gwyndolin is involved. Key items tied to the conspiracy are hidden behind illusionary walls, suggesting access to illusion magic far beyond what Havel alone could plausibly wield.
The Plot Expands
Havel joins the conspiracy. As a bishop of the Way of White, he would have ample reason to despise Seath, who is abducting maidens from the Way of White for his experiments.
By joining the conspiracy, Havel brings miracle-users and religious influence into the movement. Havel may once have been loyal to Gwyn’s order, but Gwyn is gone now.
The undead also align themselves with the Everlasting Dragon hidden in Ash Lake. This makes sense: the undead would resent Gwyn’s curse and seek a form of immortality through dragons that could free them from the affects of the undead curse before they go hollow.
The FBS himself eventually allies with dragons, as confirmed in ds3. I believe this alliance predates the conspiracy itself, though the exact reason remains unclear.
Still, it ties the FBS even more deeply to the anti-Gwyn coalition.
The Plot Fails
The conspiracy begins its attack underground, targeting Nito’s domain. This threatens one of the pillars of Gwyn’s order and allows the conspirators to seize the Rite of Kindling.
The FBS would need the Rite, if only to deny it to his enemies.
But the conspiracy is betrayed. Why and how isn't the focus right now.
One longstanding clue is the placement of Black Knights throughout Lordran. Many stand guard near corpses or locations associated with the conspiracy. But there is an odd man out, a Black Knight standing atop the tower near the Undead Parish.
Why guard that location?
If the FBS was part of the conspiracy, the answer becomes obvious: the Black Knight is guarding the FBS’s shrine.
Below ground, the conspiracy collapses. Above ground, Gwyn’s loyalists mobilize against the FBS. Seath and the Four Knights move to preserve the existing order.
With the element of surprise lost, the FBS cannot win.
The Four Knights, especially Gough, may have refused to kill Gwyn’s son out of loyalty or respect. Instead, they force him into exile.
Before departing, the FBS leaves Sunlight Blade at Gwyn’s tomb.
Velka is likewise declared a rogue deity and driven into hiding, though she continues operating within Lordran indirectly.
Erasure of the FBS
After the failed rebellion, the FBS is systematically erased from history.
Only Gwyn’s loyalists would possess the political and cultural power necessary to suppress the memory of Anor Londo’s rightful king. Seath or Nito alone could never accomplish this.
The FBS’s statues are destroyed, his shrines dismantled, and his legacy buried. Yet traces remain: hidden followers, surviving miracles, and the FBS himself quietly watching over Lordran from afar.
Timeline Concerns
Disparity itself emerges from the First Flame, including the flow of time.
Throughout the series, time is repeatedly associated with light. Filianore’s egg, for example, demonstrates that light and time are deeply connected.
As Gwyn’s Flame fades, time itself begins to distort and compress. Large spans of history lose their coherence. Centuries blur together. This is effectively how Solaire describes how time in Lordran. So if you think this seems like it happened too far in the past to make sense, I would suggest that the flow of time is convoluted.