Macbeth doesn't greet Duncan when he arrives because he is consumed by guilt and conflicting emotions about his plan to kill Duncan. His inner turmoil and ambition make it difficult for him to behave as he normally would.
Duncan
why was macbeth releuctant to kill duncan
Duncan plans to spend the night at a hotel nearby.
"I" said Macbeth, "with the servants' daggers. I killed Macbeth."
Macbeth believes he has to kill Duncan's guards in case they heard anything happen in the room while Macbeth was killing Duncan.
Duncan and Macbeth are cousins. Therefore, they are bound by kinship. They are also bound by subject and host, as Macbeth is hosting Duncan as his guest.
Macbeth was not a vassal of King Duncan. Macbeth's act of killing King Duncan would be considered regicide because he unlawfully killed his king, who was his sovereign and ruler.
Macbeth kills Duncan's grooms after Macduff discovers the body.
Macbeth kills Duncan in his own castle at night time.
They were killed by Macbeth because he blamed them for Duncan's murder.
Macbeth stabbed him when he was asleep.
To inherit Duncan's Throne