The current inhabitants of the Kingdom of Hyrule are a race of humans with pointy ears and a fair talent for magic. These Hyrulians appear to be a stable cross breed between Hylians and other races of humans, Gerudo People and common (round eared) humans from other lands.
After the decline of the Hylia they have inherited the Kingdom of Hyrule from their illustrious ancestors. several generations afterward, many disasters struck the Kingdom as the evil that had been imprisoned in the Dark World prepared to free himself. In the new timeline, the people plead to the Gods, and they themselves were saved, but the Kingdom was lost and they went to live on the Great Sea. However in the old timeline, they were saved by the Legendary Hero and with the Triforce he had brought back, Hyrule enjoyed a golden age, ruled by a just and benevolent King. Hyrule could expand far to the north and a large island east. But eventually the king died and part of the Triforce was lost. In the following generations, Hyrule experienced a cultural decline and much knowledge of the past was lost. Then once more Hyrule was ravaged as its ancient enemy returned, but again Ganon was stopped, the Triforce reunited and Hyrule entered a new age of enlightenment under the greatest king it ever had.
Inheriting their civilization from their late Hylian ancestors, the Hyrulians always had a feudal society, which as seen above alterned periods or relative harmony to others of chaos.
As for the common (round heared) humans that Hyrulians also descend from, in the world of Hyrule, settlements of common humans typically only exist outside the Kingdom of Hyrule (with exceptions in determined periods like Kakariko at the time of Zants invasion), such as in the province of Ordon or the land of Holodrum. We do not know much about them, but there was once a human kingdom in the land of Labrynna in a time predating Hyrule's Civil War. However in the ages that followed that kingdom came to an end and during Hyrule's golden age, human lands such as Labrynna and Holodrum were directly subject to Hyrule's political influence.
While common humans most likely exist in the world of Termina, we know nothing of them.