Hallyne

Hallyne, sometimes called Hallyne the Pyromancer, is a character in Game of Thrones. He will be played by Roy Dotrice and will debut in the second season.

Hallyne is the head of the Alchemists' Guild in King's Landing, in charge of the city's stocks of wildfire and concerned with other fire-related matters.

In the books
In the Song of Ice and Fire novels, Hallyne is a self-important man frustrated with the Guild's fall in power and influence since the reign of the Mad King.