|Allegiance|| House Roxton|
|Died||In 130 AC, at Tumbleton|
|Book(s)|| The World of Ice & Fire (mentioned)|
The Princess and the Queen (mentioned)
Ser Jon fought on the side of King Aegon II Targaryen and the greens during the Dance of the Dragons, a civil war between Aegon II and his half-sister, Princess Rhaenyra Targaryen, over the Iron Throne of Westeros.
At the Battle on the Honeywine, Lord Owen Costayne was mortally wounded by Jon's black Valyrian steel blade, Orphan-Maker. Jon was a member of the Caltrops conspiracy, which wanted the dragonriders Hard Hugh Hammer and Ulf the White dead, in no small part due to their outrageous demands for lordships and kingships in return for their dragons joining Aegon II's cause.
During the Second Battle of Tumbleton, "Bold" Jon slew Hugh Hammer when he least suspected it, splitting him from groin to throat with Orphan-Maker. Shortly thereafter he was killed by Hugh's men in a ten against one fight. Jon managed to kill three of them before he himself was killed. Legend says that he slipped on a part of Hugh's entrails in an ironic twist of fate.
- Jon to the other Caltrops
Jon: Lord Hammer, my condolences.
Hugh: For what?Jon: You died in the battle.