'Game of Thrones' Season 7 spoilers news: Jon Snow's parentage may affect Daenerys' conquest of Westeros
The shocking Season 6 finale of HBO's "Game of Thrones" may have confirmed the long-standing rumors surrounding the chief characters of the series. Specifically, the fans have always questioned whether Jon Snow (Kit Harington) is actually the bastard son of Ned Stark (Sean Penn), and with an interesting vision from the past, it was confirmed that Ned is not Jon's father, although the two remains related by blood. However, the news about the possible father of Jon may not be good for Daenerys Targaryen (Emilia Clarke), who is now on her way to conquering Westeros and each of the Seven Kingdoms.

As noted by MTV, the rumored R + L = J plot twist was almost confirmed in a vision by Bran Stark (Isaac Hempstead Wright) when he saw a younger Ned Stark visiting his sister Lyanna in her deathbed.
It was revealed that Lyanna gave birth to a baby boy, and that baby is no other than Jon Snow himself. There is a possibility that Lyanna's captor, Rhaegar Targaryen, is actually the father of that baby, and it were actually true, Jon will be a rival to Daenerys as the head of the House Targaryen.
If all else fails, then Daenerys may have to kill off Jon to be the sole claimant of the Iron Throne, as Dany's claims to be the only living heir of the Mad King Targaryen.
However, it is also possible that Daenerys will have to marry Jon instead of resorting to bloodshed. Besides, the Targaryens are known for inbreeding practices where siblings marry each other to preserve their pure dragon bloodlines.
Unfortunately, this practice also led some of them to madness, just like what happened to the Mad King. To recall, Dany also mentioned in Meereen before heading towards Westeros that she may have to make stronger alliances to strengthen her power, and in order to do that, she needs to marry someone eventually. That person may be Jon Snow, her possible nephew.