Giants

Lost to the depths of time and the world , the mighty titans once strode across the world, forming it from primordial elemental chaos. Ruling over the land as its sole power for five thousand years, the giants control suddenly and catastrophically failed, casting them into near-extinction and shattering the world once more. Now only existing in small numbers in the deep, dark places of the world, the giants survive and build and wait for the world to be ready for their rule once more.

Origin

The "history" of the giants is more of a mythology. Words here are colored by the language of myth and legend, and are not necessarily true to the letter. Note, too, that very little of what is written here is known to anybody that lives today. This is true prehistory, and even the most learned will only know fragments of the truth of this time.

When the world came into being there was only chaos. Raw elemental forces, the very force of magic with no control and infinite energy, raged over the burnt and empty land. This storm of pure elemental power flowed over the world, but like a mundane storm today, it moved in eddies and whirls and gigantic spinning clouds. It was in the nexus of a hemisphere-sized storm of magic that enough energy was forced into a compressed space to ignite into the spark of intellect. From intellect came awareness, and from awareness came a desire for form.
The first and greatest of the titans willed itself into being.
This First Titan was a creature of pure magic, imbued with the power of the elements, and the will to use that power to create a dominion. After becoming familiar with its abilities and coming to term with its existence, the first titan began to create order. Imposing its will upon the land, pushing back the storm, and finally - when its own hands were not strong enough - creating others of its kind from the same elemental nexuses that it was birthed from.
The giants, as a species, had come to be.

Realm

Over the next millennia, the giants would bring order to much of the world. They first began by using pure will to push back against the chaos, creating small pockets without the storm. They found, however, that these pockets would collapse without a will continually focusing upon them. The giants would take that knowledge and craft gems capable to holding a small amount of their will indefinitely. Given a power source, these gems would then push out and create a permanent space of ordered reality.
Using these gems in a growing and complex web, the giants would take control of an ever-expanding sphere of the world. Within, as their whims took them, the raised mountains, dug rivers, and gave small fragments of will into the creation of smaller forms of life. Mostly plants and early wildlife, but on occasion the desire for lordship would lead them to create intelligent but subservient life. It was in this way that many inherently magical sentient species were created, especially the Dragons and Elves .
The giants did not push their domain to cover the entire world - their number was never large enough to do so. Even with the constructs they had created, there was a limit to their aggregate power. In places, they would simply leave the chaos unfettered - the Firelands are a remnant of that time. In others, they would build enough order to make a land safe, but would build fortifications to protect against incursions. Such a fortification remains today in the form of what the Humans call the Titan Wall - named for its size, the humans not knowing how accurate that name was.

Fall

The complex web of enchantment keeping order in the world was not flawless. In places, small failures could occur, due to a loss of power in a gem construct or other accident. For the most part, though, the interconnected and overlapping spheres of order were stable - they lasted thousands of years. However, the entire system was centered upon and ordered around a single point - a gigantic gemstone anchored at the top of the tallest peak of a continent in the northern hemisphere. Over the millennia that the giants' realm existed, that mountain had been silent. But underneath, the forces of pure elemental fire and earth had been seeping upwards. Eventually, the pressure within the mountain became too much, and the mountain shattered.
The volcanic eruption initially started off small - a crack of earth, a caldera forming. But it was enough to disrupt the key point in the giants' web. In a flash, the sphere of order collapsed upon itself, releasing a jolt of pure magic. This had two results - both cataclysmic on their own, apocalyptic when happening together. First, the interconnected web of order that the giants had created suddenly overloaded as the stress of maintaining its existence without the keystone became extremely high. This may have held if not for the second event.
The second result was that the jolt of magic, combined with the sudden release of pressure previously holding the mountain down, caused the volcanic eruption to shift from a minor event to a world-sundering explosion. The mountain itself shattered, leaving behind a broken skeleton of itself. A pyroclastic flow of enormous proportions raced out from the volcano, wiping across the continent. And superheated rock and magma and ash rained from the sky across the land, burying much of the giants' creations and snuffing out life everywhere.
Elsewhere, as the ordering web collapsed, similar eruptions and elemental outbreaks happened. Oceans rose and washed across lands. Storms of wind and lightning and boulder-sized hail wiped out everything across others. In the end, the world would remain in a state of wild magic for two thousand years to come.

Today

The collapse of their world nearly extinguished the giants entirely. An extremely small number were underground when the cataclysm occurred; sensing the collapse that had occurred, they dug deeper and deeper. Using the same methods that allowed them to create an ordered realm on the surface, they carved out a subterranean refuge. Thus, hidden away below the land, the giants sit and wait. Occasionally one will venture across their underground realm, seeking out remnants of their early days, but their existence remains a secret to all.

Game Notes

An encounter involving giants would by nature be extremely rare, but any brave adventurers making their way into the deep, dark places of the world could potentially come across a lone giant. Using the giants from the Monster Manual (pp.149-156) would be appropriate. The giants covered in this article are generally going to be the more powerful varieties - the more mundane giants may be used elsewhere as simply "large ogres".