The orcs were expecting an epic battle since they have been denied a lot of opportunity to participate in the previous fights with their foes. Prepared and eager for a good fight, the orcish horde was expecting a satisfying engagement with their foes.
Khao'khen himself was expecting a huge battle with their foes especially after learning that their foes received such a huge number of reinforcement which is why he was prepared to expose the presence of his horde to their enemies since he had no choice but to mobilized them since the capability of the Drakhars was by far subpar against such a huge number foes. The Drakhars might be almost invincible against a frontal assault but their formation was without a weakness, a flanking maneuver or an attack from their rear would greatly devastate them which was why they need the aid of their light cavalry to deny their foes of such an opportunity or repel them from fully executing one.