Can Asmodeus' AD&D and 3.5e backgrounds be merged without losing anything?

Question

I was originally planning to make Asmodeus the ultimate bad guy of an upcoming campaign I am DMing, but when I discovered the background in AD&D's Guide to Hell I was immediately sold on the concept of the conflict between Jazirian and Ahriman, so I want to go with that.

The thing is, we're playing 3.5e where the backstory of Asmodeus is a bit different (the whole "I can mete out punishment for mortals: sign this contract and skip the fine print that says I can tempt them into evil), but I feel is not mutually exclusive. The main problem I see with this is that the moment his avatar shows up amongst the angels, Jazirian would recognise Asmodeus as the avatar of Ahriman and have his sorry butt eaten by five dozen angry flying feathered snakes. So I was wondering, could Ahriman create an avatar that could fool both Jazirian and the gods themselves? Or perhaps have Jazirian know the truth of Asmodeus, but not tell the other gods for reasons of her own?

Now of course, you could invoke the "your campaign, your rules" thing, but I would prefer to try and stick to the story without messing too much with it. I think that Asmodeus' background as presented in Guide to Hell and Fiendish Codex II can be put together as follows:

• Creatures of Law are born from the primordial chaos, the mightiest of whom are Jazirian and Ahriman.
• The two form an ouroborus, and create the Outlands, the Unity of Rings and the Rule of Three. They get into an argument over the Center of the Multiverse and tear each other's tails off.
• Jazirian flies to heaven, makes her realm on the fourth layer of Celestia. Ahriman falls to Baator, becoming grievously injured.
• Other gods begin to rise up and take the fight to the demons. As one of the first steps of his scheme, Ahriman creates an avatar called Asmodeus, who poses as an angel.
• Asmodeus invents punishment for sinners, and is asked if he could please not rip folks' skin off by cutting them at the waist then pulling it off like a grotesque sweater right in the gods' front yards. He agrees, and writes the Pact Primeval so he and his fellow angels can move to hell and continue their torture there.
• Baator is completely barren, but Asmodeus uses his powers as Ahriman to make it inhabitable, and gets called out by the gods for this. He pulls out the Pact Primeval and a novelty oversized magnifying glass and shows them the fine print. The gods get sick of him and cast him out, stripping him and his kind of the status of their angels.
• Ahriman pours himself a martini the size of a lake, sips it and mutters "Just as planned".

And then all of history begins to happen. Sure, I've been thinking about adding in Zargon and He Who Was, but I'm not sure how to do that quite yet. But anyway, could this above story be in line with how the backstory is described in the Guide to Hell and the Fiendish Codex II?

Answer 1

Asmodeus is actively spreading lies about himself

Everything we think we know about Asmodeus, we think we know because Asmodeus wants us to think them. All of the stories about his origins, deeds, difficulties, and triumphs, are heavily, actively, and constantly monitored, filtered, and altered by Asmodeus and his agents. Nothing known about him in AD&D or 3.5 is known for certain.

Thus, it’s trivial to reconcile the different stories: none of them are true. The contradictions exist because they aren’t accurate histories, but rumors, fears, and most of all, propaganda. In reality, the truth is probably something entirely different.

Almost all of my knowledge comes from afroakuma, who runs an amazing AD&D/3.5e Planescape Q&A thread on Giant in the Playground. He neatly integrates all of the editions, supplements, and retcons, has access to very-nearly every relevant source, and has a nigh-encyclopedic knowledge so far as I can tell, so I recommend asking him your questions, too.

Answer 2

I have been called for, it appears.

Canonically, of course, every origin or background of Asmodeus is a lie of some kind. While it's definitely accurate that he fell into Hell from elsewhere, and reasonably likely that his most well-known appearance is not the true nature of him, no one account best encapsulates the reality of what the Lord Below is.

That said, if in your campaign you want both of those stories to be true, here's what I would recommend:

The forces that Asmodeus commanded as a divine champion against chaos were not the forces of good; the Fiendish Codex makes abundantly clear that he was a champion of Law. If weakened Jazirian retreated and became a "god," it follows that weakened Ahriman might have hidden as a servant of these "gods," to discover their natures and find a means to undo them. The true nature of him would have been irrelevant, for Ahriman was indeed a great entity of Law and in his heavenly aspect would have been a celebrated asset for the still-unified conclave of Lawful deities, good and evil. Jazirian would be reduced to one voice out of many in the throng, making accusations that... what? Asmodeus wasn't nice? Say what you will about him, he's Lawful to a tee.

While Ahriman's body bleeds out in a barren and terrible corner of the multiverse, Asmodeus puts a plan into motion to seize total authority over that plane, recovering his true form and protecting it from the interference of Jazirian or the other gods. Binding himself to the powers of Law, he secures safe purchase of his living tomb by leading the forces of Law against the demons, ensuring they never strike as far as Hell. In negotiating the execution of his duties apart from the godly realms, he strikes a deal that serves him with a source of power from which to regain strength over the eons and lets him undermine Jazirian and the other gods by stealing their worship. Ultimately, by choosing to become something weaker, a mere shade of his own magnificence, Ahriman becomes Asmodeus, a wholly unique entity with a much stronger position compared to the other Serpent of Law.

Will that work for you?

Answer 3

I prefer the Forgotten realms version of Asmodeus compared to the ones present in any of the other systems that I've played in.

The story that I've heard is that Asmodeus was an archdevil in hell that essentially made it his goal to end the war between the demons and the devils.

During the spellplague when Mystra's domain was ripped from the planes Azuth was hurled into the Nine hells and his divinity was consumed by Asmodeus. After this happened he ascended to deific power, and used his newfound abilities to hurl the abyss into the center of the elemental chaos.

Asmodeus was also the original fallen-angel who negotiated with the goods of the good planes to sign The Pact Primeval, which was agreed upon to be a form of retribution and punishment which allowed them to torture evil souls to be harvested as a form of energy in the abyss.

It was in The Pact Primeval that the Faustian pact was created as a way for devils to harvest souls. The rules of the Faustian pact are (as I understand) thus:

1. You cannot magically coerce a creature into signing a faustian pact, they must do it of their own free will. Upon signing a pact the soul is marked with the mark of the demon who created the pact.
2. You cannot coerce a creature into signing a pact under threat or duress. If it can be proven that a pact was signed under duress the pact will be broken.
3. If you create a contract with a reward you must provide compensation. If it can be proven that you did not reward the signatory of the pact prior to his death the pact will be nullified in a court of hell.