The lore of Dark Souls can be impenetrable and confusing at times. Players are expected to pay close attention to dialogue, environments, and item descriptions, then interpret what they can about the games' story from there. Still, few things are as confusing as the answer to the question: Who are Dark Souls 2's Giants?
The story of Dark Souls 2 revolves around the Dark Souls games' cycle of fire and the Undead curse, two mystical properties that define the games' universe. The player spends the entire game exploring the decrepit civilizations of past cycles, learning about their tragic falls to ruin. The most recent and most important of these civilizations is Drangleic. Drangleic closely mirrors the city of DS1's Anor Londo in many ways, but unlike its predecessor, it is mostly defined by its conquests. Long before the kingdom fell, King Vendrick waged two major wars against a race of tree-like humanoids known as Giants, emerging victorious in both conflicts.
The problem with Dark Souls 2's Giants is that there was already a race of Giants in DS1, but these were incredibly different. While both races were humanoid and grew to enormous sizes, the Giants of Dark Souls 1 were much closer in appearance to regular humans. They were usually covered, but DS1 Giants had faces, and they mostly served as slaves or servants in Anor Londo. They would also communicate with the player on various occasions. This is a stark contrast to Dark Souls 2's Giants, who had a gaping hole where their face should be and came into direct conflict with Drangleic. They have no origin in the landmass that made up either Anor Londo or Drangleic, and they are able to turn into actual trees upon death. The fact that no Dark Souls 2 Giants ever communicate with the player only deepens their mystery.
The Difference Between Dark Souls 1 & 2's Giants
Even more confusing is how DS2's Giants fit into the lore. The creation myth told in Dark Souls 1 explains the origins of the universe. It fleshes out the stories of Dark Souls' major races, from Dragons to gods and Demons, but it makes no mention of any Giants whatsoever. Players can safely assume the Giants of Dark Souls 1 were another form of pygmies, precursors to the gods and humans. Unfortunately, players only know that Dark Souls 2's giants came from another land. Beyond that, their backstory remains an enigma.
Even the lore surrounding them in their own game is incredibly vague. It's stated that Vendrick stole something from them, but whatever prize he took is unknown. It is known that he initially invaded their land at the suggestion of his queen, Nashandra, and he brought many of their numbers back with him, in addition to this prize. The giants Vendrick brought to his kingdom were used for inhumane experiments in an attempt to learn the nature of the soul. These experiments resulted in the existence of Golems and DS2's Ancient Dragon.
The player travels back into the memories of several Giants near the end of Dark Souls 2. There, they see the second war between the Giants and Drangleic firsthand, and they even defeat the King of Giants during their counter-invasion. Still, the player learns next to nothing about the Giants from these encounters. Every Giant in the game is hostile, and their tragic loss and abuse at the hands of Vendrick and his men means the player has no chance at unraveling their secrets. Like so many other things in Dark Souls lore, players can only interpret what little they do know and form their own theories about the games' events.