The wolves have high hp, but they are 30% weak to slash, and no resistances to any element or status effects. Both Etre and Nasha will appear later in the fight on the right side of the field as reinforcements.
If you are having difficulty with this fight, you can start the fight with the "Initial Placement" option on, and move your units closer to just one of the sides. The left one may be easier to avoid Etre and Nasha while you're fighting the wolves.
Both Etre and Nasha are weak to confusion status. Available from Ramada and Miranda if you're trying to clear with water units only for the mission.