This article came from a question on the Gloranthan Digest following a thread regarding the slaying of Basmol and changing myths. I had already formulated some ideas on how HeroQuests were myths how myths could be changed through HeroQuesting, but I wanted a way on describing this so that it could be visualised. This was the result. I have amended it slightly from the original but the gist is still there.
In my opinion, the God Plane can be described in this way:
The God Plane is made up of the HeroPaths within it. Every Hero Path affects the God Plane and the God Plane affects every Hero Path. Each HeroQuest follows a Hero Path and, when performed on the God Plane , has an effect on the God Plane.
Think of the God Plane as a flat surface and each HeroQuest as making a mark on the God Plane, inscribing a pattern in the surface. Powerful HeroQuests make deeper and wider gouges. God Quests make huge canyons in the God Plane surface. Without Hero Paths, the God PLane would be a featureless plain, without character or distinction. The Hero Paths themselves make the God Plane what it is.
Now imagine Hero Path A having a certain effect. This marks out a pattern A which people can now follow. Imagine a HeroQuestor performing this HeroQuest on the God Plane and making a modification to this path, creating HeroQuest B. This also makes a pattern in the God Plane. If these are weak HeroQuests then pattern A will be about as deep as pattern B and people will generally be able to follow either Quest. Imagine the case when Pattern A is like a Grand Canyon. Pattern B needs to be very deep and wide, otherwise it is overwhelmed by Pattern A.
For example, in the case of the Tada/Basmol quest, the Quest where Tada kills Basmol is very deep. Any new Quest would be virtually insignificant and would be, at best, minor variants of the main Quest. The new Quest would be strengthened by Questing, but each time the new Quest failed, it would strengthen the Tada kills Basmol Quest.
This is why it is very hard to change established deeds by major deities in the God Time. It is also why changing minor deeds by demigods or spirits is relatively easy and why the God Learners were useful - they made small changes to demigods at first, only afterwards trying to make larger changes.
There is a paradox in this in that when two conflicting Quests exist, EACH ARE TRUE, although the truth of the stronger Quest is self evident through Questing.
When a Hero Path is modified and a minor variation is introduced, the two Hero Paths are very similar. Imagine this as a groove that has a point part-way along where an offshoot of the groove leaves the groove and then re-enters the groove further along. To most people, this is incidental as the start and end points are the same. To particular HeroQuestors it is important as this is where they cross the river on a floating log rather than being helped by Mr Otter.
What happens when a Myth is changed that refers to an event within Time? Does this change History?  I would say no, simply because we have to differentiate between the Hero Path and the Event. In the same way that a HeroQuest is a Hero Path linked to a series of actions, Mythical History is a series of Hero Paths linked to Events. When a Hero Path that was created after the Dawning is altered this does not change the original Event but does change the Hero Path or Myth. In actual fact, the original Hero Path is not changed but another Hero Path is created alongside it. If this new Hero Path is stringer than the original Hero Path it will appear as though the Myth has been changed. Any further Events associated with the Hero Path will be associated with the stronger version of the Myth so it would appear that History has been changed, although the Past has not changed.
So, when Nysalor cursed Kyger Litor and Gbaji wounded Korasting, this created the Curse of Kin. This time in History is a combination of the Hero Path and the Event. The Event was the cursing of the Trolls by Nysalor/Gbaji in History. The HeroPath was the myth of Gbaji wounding Korasting. Now, many trolls have tried to break the Curse of Kin through HeroQuesting and some have partially succeeded, although most have failed. One attempt caused trollkin births to happen in litters of multiple trollkin. This was a minor change in the Hero Path as some protection was given to Korasting and her fertility was increased but nobody thought that History had been changed. If the trolls broke the Curse of Kin this would not mean that all trollkin would become Dark Trolls, nor would it mean that no trollkin would have been born as these Events had already occured and are part of the Past. What it does mean that any new Events (birth of trolls) would be associated with the new Hero Path (Korasting defending against Gbaji) and the births would be of Dark Trolls.
Another example is the slaying of Basmol. If the Basmoli HeroQuested and continually defeated the Waha/Tada HeroQuestors then they would strengthen the Basmoli Survives HeroQuest enough that they could prove that Basmol had not been killed. What would this mean? Does it mean that the whole of Basmoli culture and history would unravell and lose cohesion? No, it would not. If the Quest succeeded and Basmol was proven not to have been killed, the future generations of Basmoli would look back at their ancestors and say "It is a shame that our ancestors spent their lives thinking that Basmol had been killed. We are lucky that we found out that he was not killed and that he is with us." In the far future, they may well forget that Basmol was ever thought to have been killed. If the Basmol escapes Tada Quest became super-dominant then people would be amazed that anyone tried to perform the Tada kills Basmol Quest as it was doomed to failure so why bother.
Repeating HeroQuests strengthen them and tend to make the Pattern deeper and stronger. Think of this as running a nail along the groove, this will make it deeper and wider, especially if this is repeated time and time again. Similarly, HeroQuests that are not performed become weaker and weaker until they are forgotten. Treat this as though the grooves silt up over time, maybe by wind-blown sand, unless the HeroQuest is performed the sand will build up and hide the groove.
Myths must be continually strengthened otherwise they will fade away. So, cults have Holy Day ceremonies that strengthen myths by performing Holy Day HeroQuests; common myths are strengthened by HeroQuestors performing the Quests repeatedly; enemy myths are strengthened by the perfoming of Quests and by the inclusion of the enemy's myth in the Quest. So, whenever a Storm Bull cultist performs the Eternal Battle Quest, he strengthens the myth of Ragnaglar, in particular Ragnaglar Being Defeated or possibly Storm Bull Being Defeated, depending on how the HeroQuests ends up.
1. Hero Path - what's that?
A Hero Path is the Mythical Portion of a HeroQuest. It is the path that HeroQuestors walk when they perform a HeroQuest. The Quest itself is the action of walking the HeroPath combined with the results of those actions. A HeroQuest without a Hero Path is an adventure. A Hero Path without a HeroQuest is a Myth. The two must be combined to make anything meaningful.
2. HeroQuests do not have to be performed on the God Plane, in fact most HeroQuests are not performed there. However, any actions performed on a non-God Plane HeroQuest do not stick, in other words those actions are only important for the particular time that the actions were performed. In order to change a Hero Path permanently, one must perform the HeroQuest in God Time and then change the Hero Path by either inserting a new Station, substituting a similar Station or using a Station to change the current Station. So, no matter how many times Dongo has performed the Zorak Zoran gives Yelmalio one up the arse variant of the Hill of Gold, that particular variant has no Mythical basis until he performs it on the God Plane.
3. This is important to Glorantha as the Compromise says that History cannot be changed, or so I believe. Hopefully, this will explain why History has not been changed.