Groundshakers are massive creatures that can be found in the Cradle. They are generally divided into two categories: terrestrial groundshakers, of which the twins Tharumagi and Targhizizi are the only two known living examples, and voidborne groundshakers, those unintentionally brought to Kishar when the Eitan elves built the aeroliths.
Description
Groundshakers vary widely in appearance - their size is their only real shared trait. Even still, some are considerably larger than others. Tharumagi and Targhizizi are both over 500 feet in length, larger than all the voidborne groundshakers. Most have at least a passing similarity to smaller terrestrial creatures, whether that be a lizard, mammal, insect, or something else, though typically with greatly altered physiology in some way.
The twins are generally quite passive, caring little for the lives of smaller creatures around them. While in the past they were known to occasionally crush villages underfoot, they always did so unintentionally and never out of malice. The voidborne, meanwhile, seem to have an inherent urge to destruction. Their lives are consumed by cycles of battle, formerly against the elves but now almost entirely against each other. Their brief but violent clashes punctuate long periods of quiet, as though they evidently cannot kill each other they can certainly do enough damage to require decades of slow healing.
Powerful magical abilities and seeming immortality is universal amongst the groundshakers. Their only apparent weakness is an odd aversion to water, the only thing that has kept them isolated to the Cradle.
Origins
None know of the origins of Tharumagi and Targhizizi, nor how old they are - the groundshakers themselves either do not know or don't care to share. The ancient stories of the elves of Hinthial recount that they have been around since long before the unification of Eita.
The voideborne groundshakers, meanwhile, are somewhat more recent arrivals to Kishar. When the elves of Eita brought the ansharite skymetal asteroids to Kishar for the purposes of constructing the aeroliths, they found that while most were barren chunks of rock and metal, some carried passengers entombed inside. Several of the asteroids brought to ground contained strange seeds frozen in the void of space. But seeds were not all the asteroids contained. A rare few brought something even more startling - giant eggs of alien creatures, never before seen on this planet. Once exposed to the oxygen and heat of the atmosphere, the creatures in these eggs began to develop. Initially carefully studied by the elves, these beings became impossible to contain due to the sheer size to which they quickly grew. These lifeforms, some of which were hundreds of feet from end to end, began to wander the Cradle freely, impossible for even the colossi to restrain.
In culture
Ultimately the presence of the voidborne would be one of the major factors in the collapse of Eita and the elven exile to Hinthial. Though the elves of the Cradle eventually learned to keep them at bay, in doing so they lost too many of their colossi to sustain their defenses. By Y7100* it was clear to the elves that continuing their society on the Cradle was untenable. In a mass migration north, the majority of the elves of the Cradle left their remaining cities and relocated to Hinthial, where new communities had already been established. The land bridge between Hinthial and the Cradle was intentionally sunk into the sea to prevent the groundshakers from following, in an act often considered one of the last great feats of elven magical engineering.
The groundshakers have long been subjects of worship. Cults to Tharumagi and Targhizizi date back to Eita, while those to the voidborne are a more recent phenomenon. Cults that worship the twins see them as stoic and benevolent guardians, or sometimes as teachers, while those that venerate the voidborne do so in awe of their destructive abilities, which they hope to direct towards their foes or gain themselves.