Is Lady Macbeth the real reason behind the murder of King Duncan?
No. Lady Macbeth is an accomplice in the murder of the King and his guards. Macbeth is the one who stabs them all. Lady Macbeth says that Duncan looks too much like her father. She doesn't have the courage to stab him. However, if either of the Macbeths would have been caught, both would have been executed.
The Witches give Macbeth the idea of becoming King, and Lady Macbeth gives him the plan to murder him and blame his guards and sons. But it is Macbeth, and Macbeth only, who stabs the King. Later, he will stab the two guards. Lady Macbeth has blood on her hands, sure, but she is not the primary source of evil or agent of violence, if that's what you mean. She doesn't control her husband like a puppet, and neither do the witches. Macbeth uses his own free will to stab the king.