You take another look down. There’s sand everywhere, and sand scatters easily. An invisible assailant would leave a trail everywhere.
But that isn’t what’s happening. Instead, it looks like the sand is being scattered around in large waves. Rider isn’t fighting someone off; he’s being pushed back by strong winds, or something much like them.
Which means the attacker wouldn’t even have to be nearby. You look off into the distance, still wishing you had those long goggles.
But you can still see a faint silhouette some ways off. You’re pretty sure your slicer can go that far, but you haven’t actually practiced a throw at this range. You don’t think you could aim it accurately at all, even if you did get the necessary distance. Not to mention that whatever force is pushing Rider would probably interfere with your throw, as well.
So what can you do?
Drive the horses forward to get the wagon between Rider and the assailant.
What does Rider look like he’s trying to do? Is he trying to approach the figure, or is he trying to get back on the wagon? You might be able to help him if its the latter.