Varys is a eunuch, hailing from the Free City of Lys and born a slave. At a young age, he was sold to a traveling mummer's troupe which traveled between Westeros and Essos. During his time with the mummers, he became adept at disguising himself and changing his voice. Varys was eventually sold to a man in Myr for a large amount of gold. The man fed him a potion which prevented him from moving or speaking, but left him his senses. He then cut off Varys's manhood and used them in a brazier to invoke spirits. This event left Varys with a hatred of all things magical ever since.
After being left in the streets, Varys resorted to anything he could to stay alive, including begging and stealing. It was then that he discovered that the contents of a man's letters were more important than the contents of his purse. He became one of the best thieves until he was forced out by a rival and Varys fled to Pentos, where he befriended a young sellsword named Illyrio Mopatis.
Secrets are Varys’s trade, and his skill at acquiring them has earned him a reputation for being seemingly omniscient. Crucial to his trade is a spy network of children that he refers to as his "little birds", which reaches as far as the North and even across the Narrow Sea. This reputation reached the ears of the paranoid King Aerys, who brought the eunuch to King's Landing as his spymaster. Many nobles are perplexed how such an individual earned a position on the Small Council, as eunuchs are mistrusted in Westeros. After King Robert claimed the throne, he was kept on the Small Council, though his loyalty to the throne is questionable.