Maelys Blackfyre, better known as Maelys the Monstrous, was called "the Monstrous" in part due to his freakishly large size and strength, but also due to the fact that he had a small vestigial second head sprouting out of the side of his neck - the remnant of a twin that he had absorbed in the womb. Maelys was the fifth and last Blackfyre Pretender to rebel against the Targaryen dynasty. Maelys Blackfyre was the last of the Blackfyre Pretenders to the Iron Throne. Like previous members of House
Spoilers All) House of the Week: House Blackfyre : r/asoiaf
House Blackfyre - A Wiki of Ice and Fire
Daemon Blackfyre, Wiki
Aenys Blackfyre - A Wiki of Ice and Fire
Maelys Blackfyre, Wiki of Westeros
Maelys Blackfyre, Wiki of Westeros
Who was Daemon Blackfyre's wife? How did she feel about him leaving her for a life of adventure and war? - Quora
Daenerys Targaryen – Mythological weave of Ice & Fire
Category:Individuals from Conquest & Rebellion: An Animated History of the Seven Kingdoms, Wiki of Westeros
Blackfyre Pretenders - A Wiki of Ice and Fire
War of the Ninepenny Kings Game of Thrones+BreezeWiki
Maelys Blackfyre, Wiki of Westeros
Daemon II Blackfyre - A Wiki of Ice and Fire
Who was Daemon Targaryen? What was the first Blackfyre Rebellion? - Quora
Maelys Blackfyre by Andréa Boloch : r/ImaginaryWesteros