The Edicts of Guthix, most prominently alluded to in the Darkness of Hallowvale quest, are a series of decrees Guthix created for the world after the last God Wars. Currently, there is "balance" in Gielinor between the god of order, Saradomin, and the god of chaos, Zamorak. If either god were to upset this balance by attempting to attack the other, then the other god would potentially call on reinforcements from other realms. This would escalate the crisis and lead to another devastating God War. If the Edicts of Guthix are violated, a select group of Guthixians have sworn an oath to conduct a ritual to re-awaken Guthix, causing it to remake the world without mercy for beast or man, destroying RuneScape as known by its modern inhabitants in the process. Though Saradomin and Zamorak were the main deities battling each other by the time Guthix awoke from its sleep, the Edicts also affected Bandos, Armadyl, Tumeken and Elidinis, though the rest of the Menaphite Pantheon and the other minor deities were allowed to remain because of their lesser powers and influence.
During the Darkness of Hallowvale quest, werewolves from the vampyre kingdom of Morytania were able to cross the blessed River Salve into Misthalin. They were sent by the vampyre Lord Drakan to kidnap humans for blood tithes. When King Roald, king of Misthalin, wanted to start a war with Morytania, his advisor Aeonisig Raispher reminded him that starting a war would break the Edicts of Guthix. Since then the church of Saradomin are investigating the Edicts. During the Legacy of Seergaze quest, a group of followers of both Zamorak and Saradomin is discovered who are working together to bring down the Edicts of Guthix.
When speaking to Juna the snake, there is a possibility of mentioning the Shadow of the Storm quest. After telling her about it, Juna states that Agrith-Naar found a way to get around the Edicts. This may mean that there are other ways to get around the Edicts, as is being looked in to in the Myreque quest series.
More recently, during the quest The Temple at Senntisten, one helps Azzanadra restore the Altar of Zaros in the Digsite Dungeon, the site of an ancient Zarosian city. Azzanadra then succeeds in contacting Zaros, who apparently inhabits a distant plane. Although Zaros does not come to Gielinor's plane at this time, some of his power is manifested on Gielinor, including damaging a statue of Zamorak at the Chaos altar. This manifestation is theorised to have violated the Edicts of Guthix. If this was indeed a violation, it is not known whether it was intentional or not, as the Edicts were proclaimed during the God Wars, long after Zaros has disappeared from the plane of Gielinor. Speaking to Juna after having done the quest will reveal that Zaros's return would shift things towards balance as she says that Zamorak is but a pretender god (see The Curse of Zaros for more details). However in response to the story after telling her of The Firemaker's Curse, she says she cannot look kindly to Zaros's return. Guthix also states that it has never heard of Zaros. This might make it possible that Zaros is not bound by the Edicts in the same way that other deities are, if at all.
Lumbridge is one of the portals of this realm that are most easily accessed. When your deity of choice spares your life and intercepts your passing to a different plane, it's usually just easiest to attach you to one of the many teleport spells that carry passengers from Tutorial Island to Lumbridge castle, rather than starting again from scratch with a fresh spell of our own. Believe it or not, there's a fair bit of work involved being RuneScape's resident deity of destruction, and I don't have the time to invest in letting careless PKers carry on where they left off. Besides, the walk of shame from lumbridge back to varrock teaches them a lesson about being more cunning in future.
- — Zamorak[src]
All gods of this realm have been bound by the treaty issued by Guthix not to directly interfere with the matters of mortals, nor to make our presence felt upon the land.
- — Saradomin[src]
Both Saradomin and Zamorak were compelled by my power to cease their direct interference on my world of RuneScape as when last they walked my realm it wast nearly destroyed by their squabbling.
There wast no specific incident that hath caused this, I had simply had my fill of their wars destroying my beautiful planet and prevented them from interfering anymore. They are however both mightily powerful, and I cannot fully prevent their indirect actions upon the world.As for those who say I do nothing - who makes the rivers flow? Who makes the trees and plants continue their cycles of death and rebirth? Who keeps the endless circles of Nature and Balance from breaking and bringing destruction to the lands? It is Guthix who keeps the land inhabitable, those who follow me understand these truths.
- — Guthix[src]
The gods nonetheless have left imprints and echoes of their terrible power on Gielinor and its plane, such as Saradomin's power remaining strong upon Entrana and blocking even teleporters from carrying armour and weapons to his sacred island, even through intermediate realms as the Abyss. Various objects, some of which are very common and easily attainable throughout Gielinor, such as the Holy symbol of Saradomin's silver star, has been blessed by some of the gods' most pious followers with small portions of their tremendous power, aiding them when they are praying. The River Salve, along with the Salve shards that have absorbed some of the river's holy energies, has been blessed by Saradomin's power to secure the lands of his followers against the immense threat of Morytania, as well as the god of order himself granting the Gaze of Saradomin to the Temple Knights (watching over them, his loyal followers), enabling them to respawn at Falador. Additionally, gods can influence events in RuneScape through Prayer to countless followers, mainly human. Zamorak is able to frequently attack humans who attempt to steal his wine with mystical flames, considerably lowering one's stats, albeit inflicting relatively minimal damage. The mid-level spell Divine Storm can be utilised by especially skilled practitioners of Magic, and draw upon the power of the gods themselves. Even seasoned adventurers fear the wrath of the gods, as they dare not use anything on their altars. Seren is still able to power elven magic through items such as the Crystal bow, the Crystal shield and the Crystal chime, as well as communicate with her followers through the Tower of Voices, and all but one of her nine mystic seals upon the Grand Library are still intact. Bandos can imbue certain objects with his power, which can allow him to influence the minds of whomever bears his items and to allow him to bring avatars into Gielinor. Any human bearing items dedicated to a different god than the god they are in the waiting room for is automatically forced to assume another shape temporarily, apparently due the power of the Gielinor deities. According to the Mage of Zamorak, "the magic we have had to use to retain a portal to the abyss open and effective is derived from Lord Zamorak himself. Well, he has his occasional quirks. In this case it means that when you enter this dimension you will be 'skulled' and your prayer will be drained. That makes it somewhat more dangerous than other places you may be used to."'
This is confirmed in the first RuneScape novel, Betrayal at Falador. It is mentioned in the novel that when the blood of an innocent person is spilled on a holy barrier (such as the River Salve, the Monastery, and Falador Castle), then the holy barrier is, in most cases, temporarily void. This is limited in its application, however, as more powerful barriers can only be bypassed by one individual for a matter of minutes or seconds, and often this process is unpredictable in its repercussions. This was used by Lord Drakan during what would come to be known as the War of 164, although the violation was not significant enough to invoke the Edicts.
In the 2009 Hallowe'en event, the Spider Queen reveals that the Edicts command the Grim Reaper to have the scythe, the bones, the robes and a spooky house decorated by spiderwebs. As the Grim Reaper cleans all the spiderwebs, the Spider Queen puts a spider in his bath. He must be convinced agree to put all the spiderwebs back, in order to restore the Edicts. This may conclude that the Spider Queen is a Guthixian or she is afraid of violating the Edicts of Guthix.
It was later confirmed that the Grim Reaper is a Guardian of Guthix, so him needing cobwebs in his house makes sense why it would deal with the Edicts of Guthix.
Following the events of The World Wakes, which culminate in the death of Guthix Itself at the hands of the Mahjarrat Sliske, the Edicts are destroyed, bringing an end to thousands of years without interference from the gods and allowing them to once again return to Gielinor, essentially ushering in a new Age.