Giants

Giants were the first of the hominids to rise to prominence in the primeval ages, but the last of the Primordial Titans to arrive on the scene. Granted, it is likely these primordial giants looked far different than their current descendants. What precious few records have fallen into modern scholars' hands seem to paint them as far more bestial than humanoid; their domains also having far greater influence on their appearance than modern giants, too. 
Like the Leviathans of the seas and the Dragons of the sky, the giants fell victim to The Great Diminishing and now only exist with the fraction of the strength they once commanded. There have been a few instances throughout history where giants have attempted to reclaim their lost domains from the hands of mortals like during The Long Shadow Conflicts, but each time, they were unable to overcome the sheer numbers humanity put up in defense. 
Now, giants make their homes in the far-flung places of the world; high up in the mountains or in the valleys of ancient hills. Interestingly, giants seem to be the most innately organized of the descendants of the Primordial Titans, following a rigid caste system called the Ordning. The Ordning dictates which domains of the giants are superior and which are subordinate. In order from highest to lowest, they are:

1. Storm Giants, who reside either in the clouds above the highest mountains or in the depths of the sea.
2. Cloud Giants, who make their homes in the mists that shroud ancient mountains, below only the homes of the storm giants above them.
3. Fire Giants, who live within volcanos or deep beneath the earth, fashioning weapons and armor unrivaled by even the most prolific dwarven smiths
4. Frost Giants, who roam the far frozen wastes of the north and frigid peaks of forgotten mountains.
5. Stone Giants, who have lived in the gloom of underground caverns for so long that they regard the open world above as that of a dream-world.
6. Hill Giants, who gather in clans on the outskirts of mortal civilization. Of the true giants, these are the ones most often encountered by mankind.
7. Giant-adjacent species like trolls and ogres. Ironically, these creatures do not consider themselves part of the Ordning or are even aware of it, but true giants consider them part of it all the same.

Despite their resemblance to mortal humanoids, giants boast a natural longevity in the same vein as dragons and Aboleth. They do not appear to have any upper limit on how old they can grow, which seems to be correlated to their physical size (though their height does experience diminishing returns the older they become). Some have claimed to have encountered giants that were millennia old. However, even all their strength and resilience has not saved their numbers from continuing to decline. Many predict that unless something substantial happens, giants will likely all but fade into the realms of stories and legends within the next few centuries.