Daemon II Blackfyre

Daemon II Blackfyre is an unseen character in Game of Thrones. He is not expected to appear in the series, being long dead by the time it begins.

Background
Daemon II Blackfyre was the third son of Daemon Blackfyre, a legitimized bastard son of King Aegon IV Targaryen and his cousin Daena Targaryen, by Serena Blackfyre. He had two elder brothers: Aegon and Aemon Blackfyre.

Season 1
Daemon II, along with his siblings is mentioned in the House Targaryen's entry of the book The Lineages and Histories of the Great Houses of the Seven Kingdoms.

In the books
In the A Song of Ice and Fire novels, Daemon II was the third son of Daemon Blackfyre. He appears in The Mystery Knight, the third novella of The Tales of Dunk and Egg series.