Who spared Alderpash and who actually ensured he escaped?
We had an entire AP upon preventing a Runelord from escaping (Karzoug), and an entire AP (Shattered Star) in a similar fashion.
So here, we just let him escape to wherever?
We know the threats of what may have happened if Karzoug was allowed his full power and got out into the world...now what happens if you allow Alderpash to get out?
Did anyone contemplate just what might happen if you did that (probably not as bad as Demons over running Golarion, but having him escape may not exactly be the best idea either). Will he rebuild an empire? go back to Varisia and take it over?
What exactly do you think would happen?
That sounds like a reasonable solution to a bad situation.
To be honest, Karzoug's threat was that he was a level 20 Transmuter with lots of minions at his disposal. Alderpash lacks most of those resources and while he has intelligence on what's happened in Golarion, he's also been rotting in the Abyss for ten thousand years and frankly doesn't want to return. He's got incentive to actually reform as he knows what his punishment would be.
On an amused note, if Runelords hasn't happened yet, he could very easily return to Xin-Shalast and put down the attempt to bring Karzoug back. As the first Runelord of Greed he even has a legitimate claim to the region, and assuming he's freed from the Abyss, not being stuck in some limbo realm like Karzoug means he's able to actually assert his right to rule there. (And knowing that the Mythic PCs are out there, he might even try to play it straight and reform himself while ruling the region. Perhaps even return to the original Virtue as Xin himself had believed in.)
Ah, my bad.
As I am running the campaign now, I decided to change Alderpash's motives and capabilities slightly, as I knew my party would never even think of redeeming a Runelord (they had some bad experiences with Runelords in the past). In the AP, Baphomet keeps Alderpash imprisoned with a Binding spell restricting him to his cell. I went one step further and said Baphomet bound his soul, and entreated Mother Abyss (who has been made into a theoretical overseer entity) into binding his body. Therefore, even in the event Baphomet's Binding were to fail, Alderpash would still be restricted to the Abyss by the Binding on his body and unable to return to Golarion.
Knowing this, Alderpash, being a lich, has spent his millennia imprisoned working on a new type of significantly more powerful phylactery. Since his body could never leave, even if reformed through a standard phylactery, his needed to create a living phylactery that his soul would inhabit as a new body upon his death.
Each of the players has encountered something that has drastically changed them or their powers and ascended them to higher mythic levels. One of the player characters is a unique undead Revenant-esque race with no real knowledge of how or why he came back to life, but possesses a strange form of magic allowing him to directly manipulate life force. Unknown to him, I made him the living phylactery Alderpash created through his demodand agents he was able to send to Golarion in his stead (a very inefficient and unreliable method of delivering the spells to create a phylactery, but that helps explain why it took so long to succeed).
Alderpash's connection to this player phylactery was treated as following the Corruption mechanics that started the moment the party first entered the Abyss in the Midnight Isles, slowly altering his personality towards wrath, and ulitmately ending in Alderpash's complete control. Hints towards what was happening were presented to the party, such as an encroaching necromantic and evocation aura surrounding the phylactery, the mood of anger and wrath, and when the party entered the Ineluctable Prison the phylactery was "struck" by a quick moving silver entity, which they failed to recognize as the alchemical quicksilver commonly used in phylactery creation.
When the party met Alderpash, he acted the part of a senile old prisoner who couldn't even remember who he was. I still kept his prison cell the same, including the tapestry of Xin-Bakrakhan and the shallow pool that once held the quicksilver. And wouldn't you know it, the party failed to recognize any of it. They didn't even bother to Sense Motive Alderpash much at all. I thought they knew better.
After Baphoment was slain, Alderpash made his move. He recovered his gear and made his way to the party. He took direct control of his phylactery and attempted to "fight" the party, though in reality he was hoping to be slain quickly and transfer to his phylactery's body to make his escape. When the sorcerer used Mage's Disjunction in an attempt to break the connection between the lich and the phylactery, he unwittingly destroyed the player phylactery entirely. Alderpesh, in a rage, brought in the dust ghouls (which I reasoned as being previous failed attempts), but was ultimately destroyed after the ensuing battle.
Afterwards, the party asked Iomedae to bring their companion back, but she informed them that Alderpash's work had ripped his soul away from his fate after his previous life, and it now wandered blind and aimlessly, and his removal from fate had put him beyond the reach of the gods. Instead she agreed to provide a body and the means for the party to attempt to guide his soul back, but only in exchange that one of the party take up the role as Iomedae's new Herald (which also happened to be the character that had formed a relationship with the now-dead companion. Drama!). After much roleplay, offerings, and skills checks, the soul is guided back, and the former Revenant is resurrected back into the human form he possessed in his previous life, and now acts as a Gray Paladin, with powers outside the domains of the gods.
All in all, a good time.