The Wrathstone is a powerful, mythical artifact that has been coveted by many people for thousands of years. It consists of a small, carved stone tablet with elaborate symbols and a bas-relief of a dragon's head, and it has a connection to the ancient Demon Weapon hidden within the Halls of Colossus in southern Elsweyr. At one point in time, the Wrathstone was split into two pieces, with the left side initially coming into the possession of the Dwemer of Kagrenzel, and the right side entrusted to the Ayleids of Garlas Malatar by the Daedric Prince Meridia.
Khunzar-ri and the Demons
When Elsweyr was composed of sixteen kingdoms, Kaalgrontiid and his horde of dragons came to dominate the land and consume the Moon's lunar power. To stop them, The Khajiit hero Khunzar-ri recruited four companions, Nurarion the Perfect, Flinthild Demon-Hunter, Anequina Sharp-Tongue, and the Betrayer, When fighting them proved to be futile, the Betrayer suggested that it may be best to convince the dragons that they were now a willing part of their plans. Khunzar-ri convinced the dragons to come to visit the moon temple of Jode's Light, where Anequina incited the moon Jode to emit a life draining moonlight. The dragons hungry for the moon's power eagerly stepped into it, draining them of a portain of their lifeforce, and causing them to retreat back into the wilderness. To finish the job, Khunzar-ri once again convinced the dragons to play a part of his scheme. He managed to lure them into the Halls of Colossus, where he managed to seal them away. In the aftermath, Khunzar-ri wrote on the Wrathstone in an (now) ancient Ta'agra dialect, writings detailing the cartography of the location of the Demon Weapon. The Wrathstone itself is however much older than the Ta'agra writings. The Dragons would be obscured as "demons" in legends, and become the fabeled "Demon Weapon". Their power would be coveted by many people.
Twilight of the Ayleids
Sometime after the Alessian Slave Rebellion, various Ayleid kingdoms launched a desperate search for the fabled Wrathstone, which they believed would lead them to a weapon that would be their salvation against the encroaching forces of the Alessian Empire. An expedition marched to the Dwemer city of Mzulft, in the hold of Eastmarch in Skyrim, where it was rumored the Wrathstone was held. The Ayleids besieged Mzulft, but failed to breach it or retrieve the artifact. At the time, the Ayleids were unaware that the Dwemer only possessed the left half of the Wrathstone, and that half was stored not at Mzulft, but at nearby Kagrenzel. The famed Dwemer architect Mhuvnak left Mzulft for Kagrenzel immediately after the attack to retrieve the artifact, realizing that it may need to be better guarded. It is thought that he found the defenses of Kagrenzel inadequate, and built the Vault of Mhuvnak to house it instead. Long after the time of Mhuvnak, following Mzulft's temporary fall to the Nords and subsequent reclamation by the Dwemer, the Vault of Mhuvnak was buried in a mountain of ice and lost. The Dwemer of Mzulft attempted to use their Oculory to locate the "Frostvault", but no record of the results of their search was found, and the left half of the Wrathstone was not reclaimed.
After the failure of the raid on Mzulft, Meridia appeared to her faithful with a cryptic warning that the Ayleid Empire would soon fall, and gifted the right half of the Wrathstone to the city of Garlas Malatar. At the time, Garlas Malatar was ruled by King Narilmor, who was one of Meridia's most devout and favored adherents after Umaril the Unfeathered. To keep his piece of the Wrathstone safe, Narilmor did not provide aid nor asylum to the desperate Ayleid refuges from other kingdoms, and locked them out of his city. The inhabitants of Garlas Malatar were not heard of again. Although Garlas Malatar was eventually besieged by men, some accounts have suggested that the attackers did not even make it inside Narilmor's city before it collapsed into ruin; it was suggested that the city fell from within, brought down by internal conflict or sabotage.
Lost Imperial expedition
Following the death of the Ayleid sage Tjurhane Fyrre in 2E 227, the Second Empire reportedly obtained writings of his that detailed the whereabouts of the long-lost ruins of Garlas Malatar. Around 2E 283, the city was uncovered by an Imperial expedition, which erected Fort Mistwatch within the entrance of the ruins and proceeded to plunder the city. The entire cohort mysteriously vanished and was never heard from again, however, and the location of Garlas Malatar's entrance was once again lost for the next three centuries. The fate of the Imperials proved to be a grim one: the expedition had uncovered the right half of the Wrathstone and were forcibly converted into Meridian Purified, becoming immortal yet unwilling defenders of the artifact.
Second Era discovery
In 2E 583, the frozen entrance to the Dwarven Vault of Mhuvnak finally thawed. The treasure hunter Tharayya, accompanied by Undaunted adventurers, ventured into the vault and encountered a group of rieklings who now called the Dwemer ruins their home, as well as various functional and dangerous Dwemer constructs. The vaults themselves were locked tightly, and the adventurers had to improvise by using a Dwarven delver to blast open the fortified door of the vault. The Wrathstone's vault was also guarded by a Dwarven colossus, which was taken down with the help of some skeevatons. The adventurers retrieved the left side of the Wrathstone tablet and subsequently journeyed to Garlas Malatar to retrieve the other half.
At the ruins of Garlas Malatar, the adventurers uncovered the horrors that had taken place there and fought off hordes of the Meridian Purified, who attempted to convert them, as well as Aurorans. They confronted King Narilmor, who by then had been guarding the Wrathstone for three thousand years as a Meridian Purified. Narilmor was slain, but he transformed into the Symphony of Blades, an avatar of Meridia's power in the image of an Auroran suit of armor with four arms and blades. The Symphony of Blades teleported the adventurers to the Colored Rooms, where he was able to further empower himself, but even then he failed to overwhelm the adventurers and was defeated a final time. With its chief guardian gone, the adventurers obtained the right side of the Wrathstone.
The Demon Weapon Unleashed
Subsequently after the Wrathstone was collected, Tharayya sold the stone tablet to the Imperial Chancellor Abnur Tharn. He hoped to use the tablet to locate the Demon Weapon, a weapon he hoped could end the Three Banners War. His journey would face competition, in the form of his half sister Euraxia Tharn. She had recently taken over the city of Rimmen and intended to obtain the weapon to secure her holdings and expand her territory within Elsweyr. The journey would lead them to the Halls of Colossus, where the ruin's stone engravings revealed that the Demon Weapon was not a weapon, but in fact dragons, leading Abnur to decide that the best course of action was to stop his sister from being releasing them. Abnur's good intentions would have disastrous results, as his attempt to stop the ritual to release the dragons inadvertently caused them to be released in the first place. He had brought the combined Wrathstone into the ritual, which released the dragons into Elsweyr. The Wrathstone seemingly disappeared at the end of the ritual. 
- Khunzar-ri and the Demons
- Tharayya's dialogue in the ESO: Wrathstone
- Frostbitten Journal
- In Pursuit of Mhuvnak
- Meet the Character - King Narilmor — Tjurhane Fyrre
- Face Meridia’s Minions Within the Depths of Malatar on the official ESO website
- King Narilmor's dialogue in the ESO: Wrathstone
- The Guiding Light quest in ESO
- Abnur Tharn's dialogue in the Online