Pegasus Knights are good in terms of RES, so I'd say physical damage is much better against them. Effective damage also brings Wind tomes up to 6 Might, as opposed to 3, which I personally don't feel is enough of a boost to bring our Wind mage specifically. Though, if I had to make a wild guess, I'm expecting some desert tiles, especially with flying units and mage units coming towards us, which very much leads me to believe we'll be inside Caelum territory. Though, I don't think desert tiles are enough of a reason to bring Feri, over someone else.