King Jon Snow is the son of Lady Lyanna Stark and Rhaegar Targaryen , the Prince of Rocadragón . From childhood, Jon is presented as the bastard son of Lord Eddard Stark , brother of Lyanna, and was raised by Eddard, along with their children legitimate in Invernalia but its true origin is kept secret from everyone, including Jon himself. In order to escape his condition of bastard, Jon joins the Guard of the Night and is eventually chosen as Lord Commander.
However, your decision to allow thousands of free Folk safe passage through the wall away from many of their black brothers, culminating in a riot where Jon was killed, but later revived by Melisandre. Freed from his watch of the votes of the night, Jon is running the mutineers and joins his cousin, Sansa Stark , in the building of an army to take back Invernalia from house Bolton.
After securing the help of some other Houses of the North and the vale of Arryn , which successfully retake the castle, Ramsay Bolton , to restore the dominion of House Stark on the North, Jon is declared the new King in the North by the lords of the North.