Final answer:
Donalbain does not become king of Scotland at the end of the play as his father originally intended. Instead, Macbeth becomes the king after killing Duncan, and later on, Macbeth is killed by Macduff. Donalbain and his brother Malcolm flee Scotland in order to protect themselves.
Step-by-step explanation:
In Shakespeare's play Macbeth, Donalbain does not become king of Scotland at the end of the play as his father originally intended. Instead, Macbeth becomes the king after killing Duncan, and later on, Macbeth is killed by Macduff. Donalbain and his brother Malcolm flee Scotland in order to protect themselves.