A Blaze of Valkyries

Five shiploads of Vikings against one.
This isn't her first battle with such steep odds, but this is Dyrfinna's first as commander -- and she doesn't want to see her crew be killed off by a much greater foe before they get a chance to revenge their friend Thora.
But some of these foes are called the Child-Killers, led by the bloody-minded Nauma, who glories in dealing pain and death.
Dyrfinna and her crew manage to escape to an island in order to better defend themselves as their ship goes up...