This go includes the first 4 campsite of the map, and they are the intruduction of you to Heavy Infantry.
The AI will throw you a lot of lizard-beast, meaning they'll have physical resistance, what will grow with your progression.
This means you'll need things what hit HARD, but the good news is you'll have plenty of time put them out, as all lizards only crawls, meaning they'll only step 1 hex forward in each turn instead of the usual two. The bad news is, some lizards can have elemental damage, so you won't be able to completly block them.
As Pegasi tend to have higher charges, you probably won't be able to afford that, but with any random group of high-hitters, or with a lot of elemental damagers behind a high-HP blocker can do the trick.
It is usually a good idea to concentrate cleaning only one of the two row to avoid Sudden Death problems.