What has Mordenkainen done to maintain the balance?

Question

I understand that Mordenkainen has become a wizard who strives to 'maintain the balance'. My understanding of which involves ensuring that neither good, evil, law or chaos become too strong (though my interest lies in his specific view on balance, so if I am wrong in the above then please correct me).

I have found his various adventures which seem to mostly be when he was still a player character and thus before he decided that the balance was his calling, but I can't find anything that actually says what he has done, or does to maintain that balance. All I can find is vague things like 'keeps the blood war going' and I can't even find proper sources for that (this is the most complete source, but how accurate any of it is I don't know).

From official material, including handbooks, films, computer games, quotes, interviews, notebooks stolen from the bins beside the WoTC office, or any other sources; what actions has Mordenkainen actually undertaken to help maintain 'the balance'?

I am looking for answers that can prove the reason for an action was specifically to maintain the balance, not just a list of things he might have done where the motivation is unknown or unclear.

Answer 1

Canon is long on theory, short on acts

There are many canon references to Mordenkainen acting to preserve Balance, but few if any details about specific things that he has done. I think the most detail you are likely to find comes from the Living Greyhawk Gazeteer:

Mordenkainen the Archmage formed the Circle of Eight as a tool to manipulate political factions of the Flanaess, preserving the delicate balance of power in hopes of maintaining stability and sanity in the region. Mordenkainen's view of 'enforced neutrality' is not a tit-for-tat equality but rather a detailed theoretical philosophy derived from decades of arcane research. He has fought ardently for the forces of Good, most recently during the Greyhawk Wars, but just as often has worked on darker plots to achieve his ends.

D&D: A Guide to Mordenkainen is a great site for collected official references to him.

Going beyond canon, many "old-school Greyhawkers" (myself included) suspect that he was behind the abduction of Prince Thrommel, brokering a deal between Nyrond and the Scarlett Brotherhood to insure the Prince's disappearance, just before his marriage to Jolene of Veluna would have united Furyondy and Veluna into a bastion of Good that threatened the Balance of the region.

See, for example, Greytalk Archives: Co8 and the disappearing Prince and Canonfire Forums: Thrommel!!! Aarrggh!!!.

Answer 2

We actually have very little published information on Mordenkainen, and his characterization has changed focus quite a bit over time. Unlike Elminster, who is the subject of a series of novels, Mordenkainen is only given passing mention in the sourcebooks, and he's really not in that many of them.

In short, we are told that he does things, but--as far as I can find--never given actual record of what he's done. Though, as you can see below, the development of his character has rather expanded throughout the history of D&D.

D&D 1

In D&D 1st Edition, Mordenkainen appears in the module Mordenkainen's Fantastic Adventure, where we get nothing useful about his personality--just a description of what he looks like, and that he's very well prepared for the job.

AD&D 2E

In Second Edition, he appears in the City of Greyhawk Boxed set, where this is said about himself and his companions...

Their [the circle of 8] actions are usually directed toward preventing any country, faction, or organized group from growing too powerful and overwhelming others, spreading a growing influence across the lands of Oerth. The history of this young world has taught them that great dominance arising from any quarter leads to great wars, hubris which may draw down the wrath of one or more deities, or even greater disasters

-Greyhawk: Folk, Feuds, and Factions, p.21

3e

A description of his personality is in the Epic Level Handbook

Currently, Mordenkainen leads a powerful group of wizards known as the Circle of Eight, who work to ensure that no one power gains dominance over too much of the Flanaess, and that a balance of power remains constant throughout Eastern Oerik.

and

Mordenkainen sees himself as a chief instrument of the Great Balance. His philosophies are more complex than simple equality—they are highly detailed and extremely theoretical ideals derived from decades of arcane research. Mordenkainen has fought ardently for the forces of good (most recently during the Greyhawk Wars) with his private army, the Obsidian Citadel,but just as often he has worked the side of infernal forces. [...] As a result, the wizard is not trusted, even among the likewise neutral druidic Hierophants of the Cabal, who find his vision of balance wholly self-centered and some-what arbitrary.

-Page 309

4th Edition

This time, we get a description of his beliefs straight from his 'own mouth' in Mordenkainen's Magnificent Emporium

Once I sought power for its own sake. Now I seek it to keep it from others. I do not wish to rule the world—only my small part of it. Yet many are the grasping hands of those who would claim control. Some use evil means toward such ends, while others pursue a more virtuous path, but regardless of the manner of its acquisition, power wielded to dictate over all is power used to disastrous effect. Friends will be lost, great works will be cast to ruin, and wars will be fought, but none shall gain the upper hand over all as long as I and the Circle of Eight remain.
We balance the scales.

-Page 4

Interestingly (and in contradiction 5th edition), it also says this:

I care little for [other worlds], as I am from this world, this Oerth. Just as these other worlds have similar magic items, I’m sure there are some among them who serve as I and the Circle of Eight do. Let them sort out their own problems; we have enough of our own.

5E

He shows up a few times in 5E, but the most succinct description we have of his belief structure is found here. To quote a few key lines...

they seek to maintain equilibrium across the cosmos above all. Mordenkainen and his compatriots are among its most notable devotees.
[...]
To an outside observer, a disciple of the Balance might act cruelly or heartlessly one day, and benevolent and caring the next. A follower might aid in consigning one city to domination by a devil cult while driving demonic cultists from another. For the sake of the Balance, the cosmos must remain in a static state where neither demon nor devil can permanently gain the upper hand.

Summary

In conclusion: Mordenkainen started off as an individual who believed that if any mortal organization grew too powerful, it would bring more harm than good. Keep things small, and bad things happen on a small scale. It's only been over time that this has expanded to his current "I'm the Blood War's referee" state.

But all of this is told to us, not shown. We don't get details beyond a very high level.

Answer 3

He primarily operates through the Circle of Eight.

The GreyhawkOnline wiki has a good article on Mordenkainen. (At time of writing the server is down, but the Google cache version is available.)

The short answer is that he primarily exerts his philosophy of balance by manipulating others rather than intervening personally. He does this mainly via groups he has founded like the Circle of Eight, and often by secretly sponsoring adventurers.

Some 36 years ago Mordenkainen founded the Citadel of Eight, an adventuring company of which he was a member. As they grew in power, he developed a philosophy of balance, believing that the group should use their increasing power to maintain the status quo rather than destroy evil. They generally did not take direct action, but secretly sponsored adventurers to raid the Temple of Elemental Evil. Disagreement over the Citadel's lack of action in the fight against evil ultimately led to the group's dissolution.

Mordenkainen manipulated Robilar into freeing the demon overlord Iuz in a failed attempt to slay him. Mordenkainen's reason for indirectness here was to avoid offending his ally Tenser, who was opposed to the use of assassination, and to avoid being blamed by Iuz if the attempt failed.

Mordenkainen then founded the Circle of Eight to maintain balance in the Flanaess. Mordenkainen himself was officially not a member of the Circle. The group sponsored adventurers to raid the Lost Caverns of Tsojcanth (again, the events of an early AD&D adventure). They also opposed the conquests of Iuz.

When the Hand and Eye of Vecna reappeared, Mordenkainen sent the Circle to personally retrieve the artifacts to prevent their use by evil. Mordenkainen stayed in Greyhawk for safety in case the entire Circle was killed, which did in fact happen. He mobilized allies of the Circle in a failed attempt to prevent the subsequent ascension of Vecna to godhood, and succeeded at temporarily banishing Vecna.

Mordeknainen then resurrected the Circle of Eight, who played a significant role in ending the Greyhawk Wars and Treaty of Greyhawk which ended those wars, including making peace with Iuz. He then dedicated himself full-time to operating the Circle of Eight, now a politically powerful organization which has a massive network of agents quietly manipulating events across the world.

One of the Living Greyhawk adventure module mentions that Mordenkainen operates in extreme intentional secrecy so that nobody can tell what he's going to do until he's already done it. In other words, the secrecy regarding what exactly Mordenkainen is doing is intentional on his part. We mainly only know that he's running the Circle of Eight, that they're politically powerful, and that they're doing numerous things to maintain the status quo.

The 4e sourcebook Mordenkainen's Magificent Emporium describes his activity:

Once I sought power for its own sake. Now I seek to keep it from others ... Friends will be lost, great works will be cast to ruin, and wars will be fought, but none shall gain the upper hand over all as long as I and the Circle of Eight remain.

We balance the scales.

In some cases, that means a feather's touch: a word or two in the right ear, an heir spirited away from assassins, or a storm to cast a ship off course–simple feats accomplished by a trifling of magic. At other times, circumstances dictate that our hand falls more heavily. Fortunate for us and the world that those times are few.

Answer 4

Mordenkainen Tomb of foes has a paragraph about this movement “the balance” as it pertains to 5th edition. It doesn’t mention specific actions Mordy has taken so this may not be suitable as an answer to your question, but it does specifically say that Mordy and his compatriots are some of the strictest adherences to that.

This is on page 8 which is at the start of the section on the blood war. It clarifies that the balance is soley based on ensuring neither devils or demons gain the upper hand and gives examples of the kinds of things a follower of this movement might do.