Eunuch

Eunuchs are those that have been castrated or emasculated, before or after puberty. Most eunuchs are slaves or freedmen, with some exceptions.

They are much more common in Essos, and in the Valyrian Freehold, than in the Eight Kingdoms of Westeros.

Eunuchs in the Freehold
Most slaves in the Freehold are slaves, with a majority coming from the slaver cities of Yunkai and Astapor.

As Yunkai instructs slaves in the arts of pleasure, the majority of eunuchs from Yunkai are castrati, that perform music and/or sexual acts for their masters and/or their clientele.

The most famous eunuchs in the Freehold are the Unsullied of Astapor, which make up the city's guards, and can be purchased by slavers from other cities or by foreigners. They are fully castrated in childhood and their genitalia is sacrificed on the altar of the Lady of Spears.

Some sorcerers or other magic users create eunuchs during blood sacrifices. Additionally, eunuchs are the only servants of married women in some restrictive cities, with certain paranoid husbands fearing that male servants will attempt to seduce their wives.

Lorath's Blind Priests were eunuchs, but the religion died out centuries ago.

Eunuchs in the Bone Mountains
Almost all men are eunuchs in Bayasabhad, Kayakayanaya and Samyriana, serving as the city's craftsmen, scribes, priests, scholars, servants, cooks and farmers. Only the most intelligent, strong and most handsome men are permitted to mature and breed, becoming the city's ruling Great Fathers.

Eunuchs in the Great Grass Sea
The dosh khaleen are served by eunuchs, usually those captured by the khalasar of her deceased husband.

Eunuchs in Yi Ti
In Yi Ti, eunuchs fulfil similar purposes as they do in the Freehold. It is much more common to see eunuchs as imperial servants and bureaucrats due to fear of them seducing the emperor's wives.

Famously, the pearl-white emperors of Yi Ti were a dynasty of eunuchs, having sons before coming to the throne, but castrating themselves once they came to the throne.