Further to what? Further to murdering Banquo? Further to revisiting the witches? Further to killing Macduff's family? Further to locking himself in Dunsinane castle? These are all actions he took as a result of his fears. At any point, one supposes, he had other options.
Macbeth may resort to more ruthless and violent actions, such as ordering more murders to protect his power. He may become increasingly paranoid and suspicious of those around him, leading to further isolation and potential betrayal. Macbeth may also try to solidify his position by extending his rule through more aggressive means.
Banquo is suspicious of Macbeth's actions and the witches' prophecies, believing that Macbeth may have achieved his newfound power through foul means. Banquo also fears for his own safety and the safety of his descendants, as he knows that Macbeth is ruthless and willing to do anything to maintain his position.
Act 5, scene 5. Just after Macbeth finds out Burnam wood is moving.
Suspense
By playing on audiences fears
yes fear can cause depression and effect the brains actions
Macbeth says he fears Banquo's wisdom the most because it poses a threat to his plans. He worries that Banquo's intelligence and insight may uncover his own misdeeds and ambitions.
The witches had predicted that Banquo's descendants would become kings whereas Macbeth's would not. Macbeth resented that. Also, Banquo was aware of what the witches had said and might suspect Macbeth of Duncan's murder. Macbeth says, "My fears in Banquo stick deep."
Lady MacDuff and her children are killed in Act 4 of "Macbeth". Macbeth hires assassins to kill the MacDuff family because he fears MacDuff is plotting against him..
Macbeth is hiding the fact that he has murdered King Duncan from his wife, Lady Macbeth. He keeps this information from her to protect her and also to avoid facing her reaction to his heinous act.
I'm guessing that you are asking two questions: "How does Malcolm feel about Macbeth?" and "What has Macbeth done to become the king?" The answer to the second question is simple: Macbeth killed King Duncan in order to become king. The answer to the first question is almost as simple: Malcolm hates and fears Macbeth. I hope your command of English is sufficient to understand this answer.
stairs, hide our fires;/ let not light see my black and deep desires:/ the eye wink at the hand; yet let that be,/ which the eye fears, when it is done to see
On the battlefield, Macbeth at last encounters Macduff. They fight, and when Macbeth insists that he is invincible because of the witches' prophecy, Macduff tells Macbeth that he was not of woman born, but rather from his mother's womb / Untimely ripped (5.10.15-16). Macbeth suddenly fears for his life.