Here is what is accompanying the Forsaken in their mission
Redirock and 150 Orcs
Raiju the Exile, an Oni
100 Duergar from Thane Arzen
3 Nessian Warhounds
Izavel the Medusa
Valak and Xander's crews
Garavel, Tim and Grimnock
2 troops of 100 Bugbears each: Braden's Skull Brothers and Hekarb's Head Takers
Drow Assault Team from Mantol-Derith