Eunuchs

"I'm not killing you, just making a few... alterations."

- Ramsay Snow to Theon Greyjoy

Eunuchs are men who have had some or all of their sexual organs removed in order to make them more efficient servants or soldiers, as they are not distracted by lust or sexual matters. The practice is considered cruel in Westeros, where eunuchs are mistrusted; men are typically only castrated or gelded in the Seven Kingdoms as punishment for serious crimes such as rape. However, it is considered acceptable in many parts of Essos, as part of the vibrant slave trade which exists in many areas. Slave-eunuchs are a common sight in Essos, and the famous warrior-eunuchs produced in Slaver's Bay known as the Unsullied are among the most disciplined soldiers in the known world.

Season 1
Grand Maester Pycelle expresses distrust of and disgust with Varys, and is annoyed that a eunuch is serving on the king's small council. When discussing the death of Jon Arryn, Pycelle suggests that poison is a weapon typically used by women - and also eunuchs. He then bluntly notes that Varys is a eunuch, trying to throw suspicion on him.

Petyr Baelish talks to Varys about his disfigurement as part of a verbal sparring match, asking where his testicles are located. He notes that Varys is from the Free Cities.

Season 3
Daenerys Targaryen travels to the slaver city of Astapor to buy an army of Unsullied, slave soldiers who have been turned into eunuchs to improve discipline. Lacking male organs, they do not take part in rapes.

Varys explains the story of how he was emasculated to Tyrion Lannister. A sorcerer removed his genitals - both penis and testes - and burned them in a brazier as part of a ritual or ceremony.

Theon Greyjoy is castrated by his sadistic captor Ramsay Snow, who had heard rumors about Theon being well endowed. Ramsay then sends his severed genitals to Theon's father. When Balon receives the box, he is disgusted and gives Theon up for dead, stating that his son is not a man anymore, and is no longer important to him because he cannot further the Greyjoy line.

Known eunuchs

 * Varys, the Master of Whisperers on the small council in King's Landing, emasculated by a sorcerer during his childhood.
 * The Unsullied - warrior-eunuchs and slave-soldiers from Slaver's Bay. Castrated at the age of five by the Good Masters of Astapor at the beginning of their brutal training regime.
 * Grey Worm, commanding officer of the Unsullied forces now serving Daenerys Targaryen.
 * Theon Greyjoy, self-styled Prince of Winterfell and now hostage of House Bolton, emasculated by Ramsay Snow.

In the books
In the A Song of Ice and Fire novels, different regions are known to make eunuchs in different ways. Some only remove the testicles but leave the shaft of the penis intact, while others remove all external genitalia, both the penis and testicles. The slaver-city of Yunkai, for example, is known to make eunuchs by removing only a slave's testicles, but the slave-masters of Astapor make eunuchs by removing everything, penis and testes, such as when they make the Unsullied. A eunuch with only the testicles removed but not the penis will still lose the will to partake of sexual activity, but other slave-masters like to be sure by removing the penis as well.