Monlyth Leviathan

Among the largest terrestrial leviathans, monlyth leviathans embody the unparalleled enormity, unshakeable strength, and infinite wisdom of the mountains. They are rare and elusive creatures, only waking every hundred years to taste the joys of life and revel in primal magic. Though their size makes them intimidating and often dangerous, these creatures are naturally gentle giants, wishing only to spread the joy of life with those that do not have it. Their passivity, however, should not be confused for weakness, for hell hath no fury like a mountain scorned.
Physiology
Monlyth leviathans, unlike most other creatures that share their classification, are not actually completely biological in nature. Rather, they are made of living stone—elementals that evolved characteristics analogous to creatures of flesh. Though they vary in size and shape, most monlyth leviathans resemble giant rams made of rock, with their horned heads and mountainous bodies carried by thin yet powerful hooves. They can range from as small as 750 meters in length, to nearly 5 kilometers from head to tail. To sustain themselves, these leviathans absorb energy from the soil and sun, hibernating for centuries at a time before waking to act for a few fleeting decades. This lifestyle suits them just fine, as the average monlyth leviathan can live for tends of thousands of years, if not more.
Monlyth leviathans have the innate ability to manipulate gravity. This allows them to move and function in spite of their unfathomable scale. As a monlyth ages, its gravitational pull grows stronger, which drags more soil and stone into its form, allowing it to grow in size as the years pass. These leviathans also have conscious control over their gravitational pull, can thusly exclude living creatures from being affected by their crushing strength. Additionally, the constant cycle of growth gives monlyth leviathans an unparalleled ability to regenerate from fatal wounds.
All full-grown monlyth leviathans are practiced druids and elementalists, harnessing primal magic in order to defend themselves, nourish the land around them, and in some cases, better sustain themselves. This magic also allows them to manipulate their own bodies to suit their desires. An easy way to identify an inert monlyth leviathan is to search for ornate, swooping rock formations carved into mountainsides, as these are said to act as identifying markings and regal adornments for the great beasts. The ultimate goal of a monlyth leviathan's elemental mastery is the creation and proliferation of life, and the ultimate achievement for an individual of the species is to create another monlyth. Only through their mastery of druidism and primal magic can they continue to flourish as an ancestry.
Monlyth leviathans spend most of their lives in hibernation, becoming no more than inanimate mountains and allowing life to flourish upon their fertile backs. When they wake, they tend to stay in one place, practicing their arts and interacting with the wildlife that surrounds them. Due to their size, they are near-impossible to kill as adults, and so they rarely feel the need to move, act, or defend themselves. This allows them to focus all of their energy on their practice. When a monlyth leviathan is ready to create a new member of their host, it moves to seek out a mountain range, choosing from a most beautiful peak. With its magic, it animates the tip of the mountain's peak, which then breaks off and tumbles down to the earth, growing larger and larger as it gather stone and rubble into itself like a living landslide. When it reaches the bottom of its journey, the newborn monlyth takes refuge under the shadow of its parent, who proceeds to teach it the ways of growth, of magic, and of life. For the next thousand years, parent and child hibernate and learn together—a bond built of an ancient and unbreakable love; a craftsman and its magnum opus.
As elementals, monlyth leviathans do not have true sexes in the biological sense, though they typically take traditionally feminine names for themselves, and refer to themselves as mothers, daughters, and sisters. During their rare interactions with other species, they tend to take on a motherly and compassionate, if strict demeanor.
Habitat and Ecology
Monlyth leviathans do not typically have a natural habitat, for they themselves are living habitats for other creatures. They do prefer to hibernate in places surrounded by other mountains, or among great forests and jungles, though monlyths can be found anywhere from arctic fields to volcanic wastelands. When a monlyth leviathan hibernates, it becomes one with the land, taking on the attributes of its surroundings, albeit with a stronger concentration of primal magic. This makes them extremely desirable habitats for creatures of all sorts, and it isn't uncommon to see rare and exotic beasts calling a monlyth their home. Green dragons in particular are a common sight amidst the caves that dot a monlyth's back, and they often act as devoted guardians for the great leviathans.
Even while asleep, monlyths practice their primal attunement by creating life in the form of earth elementals. These creatures of stone wander the leviathan's body, performing repairs, facilitating the growth of wildlife, and defending the monlyth from threats too small to reasonably deal with. The older the leviathan, the more powerful these elementals become. Among the most powerful of these elemental defenders are the stone golems, which are infused with powerful anti-magical properties and a singular drive to protect and serve. These elementals are not considered to be alive in the same way a monlyth is, as they lack sentience or sapience and are generally under the complete control of their creator.