Final answer:
Lady Macbeth, from Shakespeare's tragedy 'Macbeth', is the character who experiences sleepwalking caused by immense guilt over her involvement in the murders, including that of King Duncan.
Step-by-step explanation:
From Shakespeare's Macbeth, it is Lady Macbeth who suffers from sleepwalking because of guilt.
In the play, her guilt over her role in the murders, especially of King Duncan, manifests in a famous sleepwalking scene where she tries to wash the imagined blood from her hands - a symbol of her guilt.
This behavior is a physical embodiment of her tormented conscience, indicating deep psychological disturbance due to the crimes she has been a part of.