The Eighty and One is a group formed by Demandred during the War of Power.
Not much is known about the Eighty and One, although Rand al'Thor possibly alludes that it was a counter to Lews Therin Telamon's Hundred Companions. Demandred formed this group right before attacking Lews Therin and killing Tellindal Tirraso.[1]
Likely the group was the name for Demandred's personal army, as its known that the Forsaken were not solely united in anything other than the goal of freeing the Dark One and did fight amongst themselves jockeying for power.