He is a bastard born of INCEST.
Game of Thrones Season 4, Episode 6
"the boy Joffrey, the boy Tommen,
and the girl Myrcella being born of INCEST
Game of Thrones Season 2, Episode 1
and surrender to greed,
INCEST and civil war.
Vikings Season 1, Episode 6
that they are bastards
born of INCEST and adultery.
Game of Thrones Season 5, Episode 10
the product of INCEST?
Game of Thrones Season 4, Episode 6