Wereswan

Also known as the Swan Maidens or valkyrie, the Alarch-ddyn are always female. Boy children born to Alarch-ddyn mothers are rare and may become powerful magicians but they are not initiated into the Alarch-ddyn. Many of the Alarch-ddyn are deadly warriors.

Like the Selkie, the Alarch-ddyn leave behind their skins behind in the form of a feathered cloak. They suffer a tynged whereby if a human or fey possesses their skin, they must obey them and cannot harm them in any way. Many Alarch-ddyn fall into love with their cloak-keepers. If a valkyrie is slain and her cloak taken, it becomes can serve as a powerful treasure, usually granting its wearer some form of camoflauge, invisibility or invulnerability. Most modern-era swan maidens in the three kingdoms serve powerful fey nobles or keep together under thier own leader, Sváva.

There are only a few hundred Swan Maidens in the three kingdoms and only a handful in Gwent. The only one to predominantly appear in the Blood Reign books is Sienna, who is one of Marc Caradoc's knights in Riverwind.