Ha ha the witches of Endor. I wrote a paper on Macbeth from their perspective, a rare first ...one more and they have the whole gang. Good catch!
The Witches of Endor were a thinly veiled reference to the Witch of Endor consulted by King Saul of Israel just before his defeat and demise...read all about it in 1 Samuel 28 in the Old Testament.
From the beginning of the play the Bard casts MacBeth in the worse possible light.