Question: who is aemon targaryen to jon snow?
Answer: Aemon was the maester at Castle Black and one of Lord Commander Jeor Mormont's closest advisors in the Night's Watch. He was born Aemon Targaryen and was the last known Targaryen in Westeros. He was the great-uncle of Daenerys Targaryen, and unbeknownst to him, the great-great uncle of Jon Snow.