Hi Merak,
Sit down, buckle up - this will be a long reply ;-)
I appreciate the authors view of remaining loyal to Moorcocks writings and trying to reflect the saga. However, unfortunately, this has been limited to magic only. The cults book is full of liberties. For example, A Law / Chaos / Balance Cult of Aubec that started in Melnibone? Seriously?
This was disappointing and has very little if anything to do with the saga. There is a reason why Aubec's arms and armour where used by Melnibone's emperors which Moorcock doesn't explain.
You're right that MM doesn't elucidate on this, but in 'Elric of Melnibone' he refers, time and again, to the 'Hero' Aubec - and this is a Melnibonean Emperor using regalia from a human warrior, with the story being told from a Melnibonean's viewpoint. Also, if you read the cult description in CotYK, you'll see I've been careful in framing the cult from Melnibone's point of view: I've described it as a contentious cult that wasn't supported by all.
You're quite free to disagree with the cult's origins of course, but to flatly state 'Hero worship is not it' - without providing an alternative theory - isn't very helpful. How do you
know? MM certainly doesn't say that it isn't - but his constant reference to Aubec as a Hero from a Melnibonean viewpoint suggests that something akin to hero veneration or, at least, deep respect, is plausible.
Were the arms and armour better than the Melnibonean? Exotic? They were not Sorcerous for we know how Aubec felt about that.
How did Aubec feel about sorcery? I don't think that we're ever told...
They were certainly not made by Law, as his only dealings with Law was that single meeting with Myshella. Was it as a sign of Melnibonean might over the YK? Perhaps but why use them in battle rather than as a standard? Who knows. Certainly, the reason has been forgotten by Melnibone.
But again, this is your conjecture. I agree that his regalia is mundane. But it clearly has significance enough for Melnibone's emperors to take such items into battle - both as standards but also because a great hero that even Melnibone could respect, used them. However I don't agree that the reason has been forgotten. If that was so, then Aubec's name would have been forgotten first, along with his being a hero. This isn't so, as 'Elric of Melnibone' continually reinforces.
So, to the point. Loz, why not just include 'optional' rules for object bound demons in the new edition? Its as much in the saga as the cult of Aubec so why not. That way you add flexibility and keep the old timers happy. Let people decide how authentic they want their game to be.
I agree; to the point.
Any writer using canon for a game book has to elaborate and extrapolate. It'd be a very thin and disappointing book if he didn't. Players of Elric games are always crying out for greater detail on this, that or the other and that means creating materials that, whilst having their roots in the canon (as does the cult of Aubec) most likely elaborate on it significantly and diversify it. And, because MM himself hasn't written this stuff, it will always be open to debate and interpretation; always has been and always will be.
The Aubec cult is based on extrapolating the several references to Aubec as a hero from 'EoM' and Aubec's own short story. To a very large extent its fluff that can be very easily ignored if you don't like the cult or disagree with how I've posited it (oh, incidentally, I'm surprised you haven't taken more issue with the cult of Tovik. He doesn't appear in the saga at all, but I included him as a piece of continuity with the Chaosium Elric! game

).
Bound demons are a different matter. First, there isn't
anything in the stories that hint at bound demons, binding demons or the kind of items that earlier versions of the game regularly threw up. If there was, even a slight, reference, then I'd have worked on that just as I worked on the different cults.
Second, as you've recognised Merak, bound demons create all kinds of problems. Oh, they're great fun; I've played in the YK since the first edition of Stormbringer appeared and had a whale of a time with demon weapons - including the usual scenario where all the characters were Agents of Chaos running around with 10D8 broadswords. Its fun... for a while, and then you get 'Demon Inflation' and campaign breakage. Bound demon items are difficult to balance, difficult to restrain, and for players, difficult not to abuse.
You can ignore a cult quite easily. You can drop a reference to it being a Melnibonean Hero Cult. But if the rules include even an
optional set for binding demons into items, it isn't easy to drop or ignore it. Especially if you, as GM allow the rules to be used and, within a few sessions, find that your game is actually suffering as a result. Try taking those items and rules away and see how much your players will thank you.
The demon summoning rules in MRQ Elric allow for some quite extraordinary and powerful demons to be summoned relatively quickly and to wreak havoc when they are summoned. But the rules are balanced to ensure that you get MGF but not campaign breakage. And they remain faithful to the saga.
Listen, if MM writes a story next week that has Theleb K'aarna summoning and binding a demon into a battleaxe, I'll not hesitate to include it in the new version of the game. But as things stand, I don't intend to include Binding rules even as an option.
By all means though, use the rules from 'Arms and Equipment' in your Elric games; or make up your own binding rules. Its your Elric. But, as the writer of the game, I have a duty to try to remain as faithful to the canon as possible - and that holds true for Elric just as it does for Glorantha or any other setting I'm writing for. There are some elements that can be comfortably extrapolated because they'll always be open to interpretation (until MM does something to cement that interpretation), but equally some that really shouldn't be messed too much with.
I don't intend saying any more on the whole 'Why Don't You Give Us Bound Demons' debate; I think I've explained my reasons clearly and I think those reasons are solid. What I will say is this...
Elric is my first love in fantasy fiction. It was my first love as a roleplaying game. I want to give you the best game I can and the game that's truest to the saga. Chaosium's Stormbringer was a huge, fun game, but, unfortunately, littered with a great many errors and introduced a whole host of concepts that have actually become a millstone rather than an asset to the game in terms of a legacy. I really want to try to correct that and I'm afraid it means sacrificing some sacred cows - like bound demons. I'm not trying to be precious, peevish or selective in what's retained: whatever I create or extrapolate usually has some basis or mention in canon. What I am trying to do is provide Elric players and GMs with a solid basis for recreating the Elric saga and telling their own stories at their own tabletops.