1. First appear in Act 1, Scene 1, amidst thunder and lightning, setting a foreboding tone
2. Their ambiguous prophecies and cryptic language establish them as otherworldly beings, capable of influencing the fate of mortals
3. Reappear at key moments to manipulate and torment Macbeth
4. Their prophecies awaken Macbeth's ambition and set him on a path of treachery and murder
5. Their influence highlights the power of the supernatural to corrupt and manipulate human desires, blurring the line between fate and free will