While it’s part of Norse myth that the gods and giants are enemies, it seems that the giantesses were a different story. Odin clearly never met one he didn’t like, and he was far from being the only one to have a fling with one. Even Thor the giant-smasher had an affair with Jarnsaxa. These romances usually resulted in the second-generation gods, such as Thor’s son Magni.
Sometimes, however, the sons of these unions were mortals, or demi-mortals anyway. The Swedish ruling dynasty called the Ynglings and the Norwegian earls of Hladir traced themselves back to the giantesses/goddesses Gerdr and Skadi, respectively.
