The giant races rule Tyria

According to Thrulnn the Lost — the last jotun storyteller — the Age of Giants was a time when all the world’s giant races ruled Tyria. The norn, the jotun, and other giants commanded magic of a power that "will never be seen again," and wherever they walked the ground shook. The lesser races looked up to them, for the giants were superior to all others and were gaining on the Six Gods themselves.

The jotun in particular were once a highly advanced people, full of great spellcasters and lore-keepers, knowledgeable in both sorcery and natural philosophy. They proclaimed themselves rulers of the Shiverpeak Mountains and raised great monuments to themselves on the highest peaks. Their leaders, the giant-kings, were tremendously powerful beings — as skilled in feats of strength as in magic and lore. Because the jotun kept their history orally, and Thrulnn is credited as the last of their historians, the wiki notes this account cannot be confirmed.