Guild Wars 2

The question in the title ^

Some kind of magic artifacts/ something else?

The Elder Dragons awakening does not require a catalyst, rather it seems to just be a part of their cycle. Similar to a bear hibernating for the winter, they wake up when their body has depleted their stores of magic, and return to ‘sleep’ when they have absorbed enough and are full.

If you are asking this question because of the seeming catalyst with Mordremoth waking up being Scarlet, then I can see where this gets confusing. In that case, although she did wake him up, it is more like she woke him up a bit early, he was scheduled to wake up soon anyway.

they awaken at their own (see kralkatorrik, jormag), but their awakening can also be catalyzed by natural events or triggered by people who are not controlled by the elder dragons (see mordremoth), but the worst part is, they can plan for it, they can prepare their own minions or ex-machina to trigger in an age they want to wake up in (see primordus). Primordus would’ve woken up in gw1 if we didn’t kill the great destroyer. Instead, he woke somewhere between gw1 and gw2 (I think it was about 100 years in)

Moonyeti and Amaimon are both correct- we currently believe that an Elder Dragon will wake up with or without a catalyst- but it is worth pointing out that at least three of the other dragons tried using a minion to jumpstart them into awakening. This is just speculation, but it’s possible that a risen servant left over from the last rising, if sufficiently powerful, served a similar role as the Great Destroyer, Drakkar, and Scarlet.

Global warming.

Every Elder Dragon seems to have had a “herald” champion for them – Drakkar for Jormag, Great Destroyer for Primordus. The death of the herald causes the Elder Dragon to sleep 50 more years than otherwise, but it’ll inevitably wake on its own.

Primordus and Kralkatorrik both woke up late, as their awakening overlapped with another’s (within the margin of a decade – or so we’re led to believe for Primordus/DSD); thus, they both had their heralds removed (Great Destroyer was killed, Glint was turned – some dialogue implies it happened after he fell asleep but before the other ED did, while other dialogue implies it happened while he was still awake thus couldn’t be his intended herald; if the latter, she likely killed it).

The DSD, Jormag, Zhaitan, and Mordremoth all woke up “on time” thanks to their heralds (Scarlet being Mordremoth’s last-minute-made herald).

By all indication, the Giganticus Lupicus – a champion from the previous dragonrise (told to us by Anet) – was likely Zhaitan’s herald. It’s rather speculation, but the existence and effect of the Great Destroyer, Drakkar, and Mordremoth as well as the times of awakening indicate that all had a herald, but three were made inoperable (though one, Mordremoth, got a last-minute replacement).