The significance of is greater than many understand. Ser Duncan the Tall was first mentioned in Game of Thrones, with Joffrey noting that a history book dedicated four pages to him. This confirms his historical importance, though at the start of his own series, he is merely a large man once described by his former employer as “thick as a castle wall and slow as an aurochs.”
However, by the conclusion of Episode 5 of A Knight of the Seven Kingdoms, Ser Duncan’s deeds have inadvertently triggered a monumental historical change—one that ultimately leads to his squire, the young Egg, . The explanation follows.
Warning! Major spoilers for A Knight of the Seven Kingdoms Episode 5 ahead!
Following Aerion’s demand for a Trial of Seven to resolve his conflict with Ser Duncan, Prince Baelor Targaryen, heir to the Iron Throne, stuns spectators by supporting Dunk over his own nephew, Aerion. Baelor holds an edge since the Kingsguard cannot injure him, yet he still confronts his nephews Aerion and Daeron, his brother Maekar, and Ser Steffon Fossoway.
Dunk succeeds in overcoming Aerion and forcing him to retract his claim, but his companions are severely wounded, with Lord Humfrey Beesbury and Lord Humfrey Hardying both dying from their wounds. After Raymun and Steely Pate finally escort Dunk from the field, Baelor approaches him, stating he is the sort of knight the kingdom requires. He then asks Raymun to help remove his helmet, exposing a terrible wound on the back of his head, likely from Maekar’s mace. Without ceremony, he collapses, dead.
This is not just another Game of Thrones death. Prince Baelor is the primary successor to the Iron Throne, which his father, King Daeron the Good, currently occupies. His demise promotes Baelor’s son, Prince Valarr, to heir.
Nevertheless, later in the same year the events of A Knight of the Seven Kingdoms occur, a devastating plague sweeps across Westeros, killing Valarr, his younger brother Matarys, and their grandfather, King Daeron. With the throne vacant and the next two heirs deceased, the crown passes to Baelor’s next youngest brother, Aenys.
Aenys would designate several heirs, but all met with misfortune. The first was his younger brother Rhaegal, who died choking on a pie. Next was Aelor, Rhaegal’s son, but he died in an accident caused by his twin sister, Aelora. She became the heir until she took her own life from remorse. This left the throne to an unexpected candidate: Maekar, the fourth son of Daeron the Good. With Maekar as king, his sons became the heirs, setting the stage for Egg, also known as Aegon Targaryen, to ascend the throne decades later.
Thus, although Dunk may be tormented by grief over the outcome of his actions, this was the conclusion the Seven Gods deemed appropriate. While tragic, it also guarantees the crown will finally rest where it belongs: upon the head of a former squire who is no longer bald.