Natus had been hiding before the attack started, preparing to eat. He had brought his own food; solid, tasteless, and efficient. Food that had a broth or liquid element could be dangerous, a single stain can be the difference between being spotted or being invisible. He was not surprised when the foreign army attacked, simply storing his food in a hidden pocket, pulling his bandanna over his face, and pulling out Mercy and turning her into battle form. 

He did not attack yet, the others seemed capable of holding of these grunts. What he did do is observe them, and prepared him to take out any runners when the other inevitably lost. These soldiers were woefully under prepared, which meant one of two things: They simply did not know they would run into this group, or this is simply fodder to distract us as more capable foes approached. Either way, he would have to stay alert. A single runner could be trouble, and a captive could be very useful.