Besieger

When Korin, rightful king of the Cimmerians, leaves his kingdom to seek a fabled magic sword, his sister Mara sees an opening. She seizes power using dark magic and consolidates her hold while Korin is absent. The nearby Vikings, hearing of the power shift and fearing Mara will eventually turn her attention toward them, dispatch their own warriors on a parallel quest—to recover Thor's hammer, believing it can oppose whatever she commands. The Viking party travels by flying ship until Mara's forces shoot them down and destroy their capital. Besieger is an RTS built around this multi-faction conflict in a dark fantasy world.