Son of Ser Elbert Arryn and a distant Arryn cousin, called the Darling of the Vale for his gallantry in the lists and his open hand at court. After the Mad King had Elbert butchered with Lord Rickard Stark in the throne room, Lord Jon named young Denys Keeper of the Gates of the Moon and heir-presumptive to the Eyrie. He took a Royce bride, Mya, and rode south with his foster-brother Robert in the great revolt that followed.
At the Battle of the Bells in 283 AC, Ser Denys met Lord Jon Connington in the streets of Stoney Sept as the rebels fought to keep Robert from the Targaryen host. Connington took him with an axe; the wound was mortal, and the gallant knight died before the day was out. His wife and infant son followed him into the ground within the year, and with their passing Lord Jon Arryn was once more left with no heir of his blood, a want that would be answered only by his late marriage to Lysa Tully and the sickly boy born of it.