Young Siward.
In the end it is Malcolm who finally slays Macbeth. No! Rubbish! Malcolm is a useless soldier and couldn't kill Macbeth if Macbeth were tied hand and foot. It was Macduff, the man "not of woman born", who kills Macbeth.
The cast of Macbeth - 2015 includes: Lasco Atkins as Macbeth Army Soldier Pete Buzzsaw Holland as Macduff Personal Guard Paddy Considine as Banquo Marion Cotillard as Lady Macbeth Martin Crossingham as Norwegian Soldier Elizabeth Debicki as Lady Macduff Michael Fassbender as Macbeth Mike Firth as Macbeth soldier Julian Gillard as Norwegian Soldier Sean Harris as Macduff David Hayman as Lennox Jeff Longland as English Soldier James Michael Rankin as Macbeth Soldier Jack Reynor Shane Salter as Norwegian Soldier Julian Seager as Macbeth Soldier David Thewlis Dan Twine as Scottish Soldier
And then Macbeth asked Macbeth if he confronted Macbeth on killing Macbeth with Macbeth.
Young Siward is a Scottish nobleman and a soldier who fights alongside Malcolm to defeat Macbeth. He is killed by Macbeth in combat during the battle.
Boston Massacre
it isn't relavant to the play and therefore it is not answered in the plot of Macbeth.
Macbeth stabbed him when he was asleep.
The Witches forecast the downfall of Macbeth and then vanish. (not killed by anyone)
Macbeth is a heroic soldier and an honorable man. ( apex )
Macbeth kills him because Banquo starts to work out that Macbeth killed dDuncan
Macbeth killed him, by hiring some murderers.
Mainly Macbeth, but I suppose his power-hungry wife as well.