Maelys Blackfyre was a descendant of Daemon Blackfyre (grandson, most likely) and known as "Maelys the Monstrous" because he devoured his twin in the womb, leaving him with a small vestigial head. He was the last of the Blackfyres. He became a merchant and claimed Westeros as his birthright. With the help of fellow merchants he attempted to take the Iron Throne but was slain by Ser Barristan Selmy.