Cleon

Cleon is an unseen character in the fourth season. He is first mentioned in "First of His Name".

Background
Cleon was a butcher and one of the thousands of slaves liberated after the Sack of Astapor.

Season 4
Jorah Mormont reports to Daenerys Targaryen that the council she had left behind to rule Astapor has been overthrown by Cleon, who styles himself as "His Imperial Majesty."

In the books
In the A Song of Ice and Fire novels, Cleon was once a slave owned by Grazdan mo Ullhor, serving as a butcher. It was said he could cut up a pig faster than any other man in Astapor. After gaining his freedom, Cleon stirs up the people of Astapor, claiming that the council is attempting to reinstate the deposed Good Masters. With the backing of the people, Cleon executes the council members and installs himself as king.