Denys Darklyn

Lord Denys Darklyn was the Lord of Duskendale during the reign of King Aerys II Targaryen and the last head of House Darklyn.

Background
Denys Darklyn was a knight of House Darklyn who at some point became the Lord of Duskendale.

The Defiance of Duskendale
Lord Darklyn petitioned King Aerys II for a charter that would allow him to levy his own port fees and taxes. Tywin Lannister, the Hand of the King, refused. Knowing the bad relationship between the king and his Hand, Denys invited Aerys himself to Duskendale to discuss this petition. The king accepted, against the counsel of Tywin, and traveled to Duskendale with only Ser Gwayne Gaunt and a small retinue. Denys ambushed and seized Aerys the moment he arrived outside the city gates, killing Ser Gwayne and the retinue. Aerys was thrown in the dungeons and tortured with petty cruelties such as having his beard pulled. Lord Tywin immediately raised the Lannister army and laid siege to Duskendale with naval support from the Royal Fleet, but Denys threatened to kill the king at the first signs of an assault.

After six months of siege, Ser Barristan Selmy infiltrated the city disguised as a beggar and rescued the king and took an arrow to the chest while narrowly escaping. Lord Denys then surrendered and begged mercy from King Aerys. Denys and the rest of House Darklyn were executed on the king's orders.

In the books
In The World of Ice & Fire, Denys is not mentioned to be a knight. Besides this, his story is the same.