But Jon's not only a Stark. At this point, Jon's destiny hinges on the other side of his bloodline. Jon's mother is Lyanna Stark, Ned's sister. His true father was Rhaegar Targaryen , King Aerys II's son — which makes Jon the rightful heir to the Iron Throne. While Jon aims to support Daenerys, his very bloodline makes him a threat to her claim on the throne. Now that his secret is out and steadily spreading, he's in danger from both queens, Daenerys and Cersei (Lena Headey). And, as Sansa reminds Jon, the men of their family don't fare well in the capital — even their grandfather and uncle were brutally murdered there