Why do they castrate the unsullied? - Quora
The castration of the Unsullied is the first of many physical and mental hardships used to strip away the very identity of the boys in training. In A Storm of Swords , when Daenerys first sees the Unsullied in the Plaza of Pride, she asks this question to Kraznys, who at first evades the question.
DA: 2 PA: 59 MOZ Rank: 66