King Duncan is the father of which character in William Shakespeare's "Macbeth"?
Donalbain
Title: King Duncan
Passage: King Duncan is a fictional character in Shakespeare's "Macbeth."  He is the father of two youthful sons (Malcolm and Donalbain), and the victim of a well-plotted regicide in a power grab by his trusted captain Macbeth.  The origin of the character lies in a narrative of the historical Donnchad mac Crinain, King of Scots, in Raphael Holinshed's 1587 "The Chronicles of England, Scotland, and Ireland," a history of Britain familiar to Shakespeare and his contemporaries.  Unlike Holinshed's incompetent King Duncan (who is credited in the narrative with a "feeble and slothful administration"), Shakespeare's King Duncan is crafted as a sensitive, insightful, and generous father-figure whose murder grieves Scotland and is accounted the cause of turmoil in the natural world.
Title: Donalbain (Macbeth)
Passage: Donalbain is a character in William Shakespeare's "Macbeth" (c. 1603–1607).  He is the younger son of King Duncan and brother to Malcolm, the heir to the throne.  Donalbain flees to Ireland after the murder of his father for refuge.
Title: Duncan I of Scotland
Passage: Donnchad mac Crinain (Modern Gaelic: "Donnchadh mac Crìonain"; anglicised as Duncan I, and nicknamed An t-Ilgarach, "the Diseased" or "the Sick"; ca. 1001 – 14 August 1040) was king of Scotland ("Alba") from 1034 to 1040.  He is the historical basis of the "King Duncan" in Shakespeare's play "Macbeth".
Donalbain (Macbeth) King Duncan