Macduff plans to move uphill with siward and malcolm with tree branches towards Macbeth's castle. when they arrive Siward fights Macbeth and dies because of his confidence that Siward is a man born of woman. Then Macduff comes in after telling him you killed my family and now I will let my sword speak and eventually kills macbeth.
Malcom, old siward and Macduff going up the hill
MACBETH meets old SIWARD
Macbeth kills Siward
Siward is dead
MACDUFF, old SIWARD and MALCOLM move their army uphill with branches"Now near enough. Your leafy screens throw downAnd show like those you are.—You, worthy uncle,"
Siward walks into Macbeth's castle and approaches Macbeth saying hes not afraid of him "Thou liest, abhorrèd tyrant. With my swordI’ll prove the lie thou speak’st."
"But swords I smile at, weapons laugh to scorn,Brandished by man that’s of a woman born." in other words he saying that his sword doesn't hurt him because he is a born from a woman