Final answer:
In Shakespeare's 'Macbeth,' Young Siward engages in a fight with Macbeth during the battle at Macbeth's castle and is killed.
Step-by-step explanation:
In Shakespeare's play "Macbeth," the character who encounters Macbeth during the battle at Macbeth's castle and tragically meets his demise is D) Young Siward. Young Siward is a minor character who bravely fights Macbeth but is killed. This event highlights Macbeth's descent into tyranny as he clings to power and faces the consequences of his actions.