— Marionette Control Panel
Mordremoth is the Elder Jungle Dragon and the most recent dragon to awaken. Mordremoth's existence did not become apparent to most Tyrians until early 1327 AE, when it awoke. It was, however, mentioned in ancient dwarven texts and jotun stalea, although no details other than the existence of a sixth Elder Dragon were ever made clear. Additionally, the Inquest had been conducting experiments structured around the presumption of six Elder Dragons for a while, indicating they had some prior knowledge of it.
 Pre-awakening evidence
The Infinite Coil Reactor, where the Inquest are attempting to harness Elder Dragon energies (among other things), is built in a hexagonal structure with six corners, each containing a "zone": Black, Red, Violet, White, Blue, and Green. Four of the zones (Black, Red, Violet, and White) are known to correspond to Elder Dragons (Zhaitan, Primordus, Kralkatorrik, and Jormag respectively), containing dragon minions corresponding to that dragon, and the under-construction Zone Blue, although empty, is implied by its workers to be intended to house a captured minion of the deep sea dragon. Zone Green has a nature theme, including poisonous Death Blossoms, but is otherwise empty.
The Crucible of Eternity is the interior of the Infinite Coil Reactor, and is where the experiments on Elder Dragon minions are performed. Three labs are able to be visited - Experimental Lab Red, Experimental Lab White, and Experimental Lab Green. Again, Lab Red is related to Primordus, and Lab White related to Jormag. Lab Green contains a multitude of plant creatures, including Nightmare Husks and Nightmare Hounds. Each zone also houses a powerful minion, respectively the Evolved Destroyer, Bjarl the Rampager, and the Evolved Husk, implying a connection between the jungle dragon and the Summoned Husks seen in and around Twilight Arbor. Subject Alpha, the creation of Kudu, also uses abilities enabled by Mordremoth's corruption.
There are other, possible examples of Mordremoth's early influence, but none are confirmed. Among the strongest two is Gamarien, whose Wyld Hunt calls him to protect Wychmire Swamp and fears that a "much darker force" than the Nightmare Court is at work there. There is also a Rotting Oakheart at the Thaumanova Reactor, a place associated with experiments involving dragon energy. A similar Rotting Ancient Oakheart exists in Queensdale and is described as "corrupted" by hunters, but it's possible they mean that in a more mundane sense as they are not likely to have any special knowledge of dragon magic.
Scarlet Briar, then known as Ceara, was compelled to put her plan into motion after experiencing nightmares of some dark "entity". In Ceara's journal, the sylvari complains of feeling like she is losing control of herself, and that she is being "possessed". The last entry, dated Season of the Scion 1323 AE, merely states, "It communicated with me through images of death, destruction, and destiny. I must know more. I must confront it and put an end to this madness".
The sylvari spent many years travelling the world, studying the engineering secrets of each of the races. Eventually her travels brought her to Rata Sum, where Headmaster Omadd of the College of Synergetics offered her to "see into the Eternal Alchemy itself". Ceara, unable to resist the opportunity, agreed to the experiment, entering an isolation tank, the purpose of which was ostensibly to shut down the mind's security system and open it—like opening a door—to welcome in the truths of the Eternal Alchemy. In practice, this exposed her directly to Mordremoth's influence, and broke her mind.
Vorpp, the Arcane Council's point person, noted that the only things Ceara could have encountered in the isolation tank were the things that she had brought in with her, concluding that she had been exposed to a part of her psyche that had previously been walled off—perhaps for her own protection. Vorpp also admitted, however, that a far more extensive study of the Dream of Dreams would have to take place before any more detailed conclusions could be drawn.
 Modremoth's Rise
Scarlet launched a massive invasion of Lion's Arch, levelling the city with her Molten Alliance, Aetherblade, and Toxic Alliance forces while her massive airship drill, the Breachmaker, bore down on Sanctum Harbor. With her drill, Scarlet disrupted the major ley line beneath Lion's Arch, knowing that the ley lines feed the dragons. Another way of looking at it would be to say that the dragons consume magic, and the ley lines are currents in an ocean of magic. Scarlet threw a giant rock in that pool, sending ripples out to the dragon.
Upon awakening, Mordremoth let out a roar that could be heard across all of Tyria. Why Scarlet sought to awaken the dragon is unknown, but one thing is: given that no dragon has yet risen without a catastrophe immediately befalling Tyria, the consequences of her actions have yet to be fully realised.
- Prior to Mordremoth, the other elder dragons had been awakening approximately every 50 years. Mordremoth awoke only 7 years after Kralkatorrik due to Scarlet's unnatural disruption of the ley lines, indicating that this may have been important to her plans.