The Legend of Kristen Cole

Kristen Cole is from a house on the Dornish marches, and so is Barristan Selmy. The dragon of the stepstones that Kristen Cole beat was Damon Targaryen. In the case of disobeying the king's final will, well, that's straightforward. But it's said that Damon was wielding Dark Sister, which is pretty odd for a tournament.