High Sparrow

The High Sparrow (real name unknown as High Septons abandon their names) is a major character in A Song of Ice and Fire. In the TV show he's introduced in Season 5 of Game of Thrones. He is the leader of a fundamentalist sect of The Faith of the Seven called The Faith Militant (with two orders: Warrior's Sons and the Poor Fellows) as well as the leader of the Sparrows, and later the new High Septon of the Seven Kingdoms.

Despite coming off as harmless and compassionate at first, he reveals his true colors as a fanatical zealot as the season progresses, usurping Cersei Lannister as the main antagonist of the King's Landing storyline. High Sparrow is the tertiary antagonist of Season 5 over all. He is portrayed by Jonathan Pryce, who also portrays General Vavarin Delatombe and Elliot Carver.

This man is described to be truly devote to the Faith of the Seven and has an iron will, being immune to every temptation or weakness. Before the death of Lord Tywin Lannister, he lived all over the realm and walked upon villages that were too small to have their own septs and performed the traditional duties of a septon, such as naming newborn children, absolving sins and performing marriages. He starts behaving in a more fanatical way after he becomes the new High Septon and takes control of the capital (with also the unintentional help of Queen Cersei).

The High Sparrow's plans however don't stop in King's Landing. He wants to deal with the foreign faith of R'hllor the Lord of Light, and eradicate it from the realm. He claims that Stannis Baratheon has turned from the truth of the Faith of the Seven to worship a red demon, and his false faith has no place in the Seven Kingdoms.