You should read the [[Star Dancer by Beth Webb|first book]] in the series rather than beginning with ''Wave Hunter''. [[The Mark of Edain by Pauline Chandler]] also talks about the enmity between the druids and the Romans. [[Bloodline by Katy Moran]] is an evocative story of Dark Ages Britain with a subtle fantasy element.
You can read more about Beth Webb [[:Category:Beth Webb|here]].