A Crown So Silver — Lyra Selene

The second book in Lyra Selene's internationally best-selling trilogy takes place on a mysterious snowy island ruled by a trickster king where magic comes at a price, a deadly trial commences. The prize: a chance for vengeance.
 
After her sacrifice on the Ember Moon, Fia is flush with powerful magic and eager to rush into battle against her murderous sister, Eala. However, Fia's new husband Irian suggests they bide their time and retreat to the Silver Isle, a snowy island at the edge of the fae world.
 
Ruled by the cunning smith-king, the Silver Isle proves far from a safe haven. Fia and Irian become embroiled in the Tournament of Kings competing for a magical forging of immense power. Their relationship will be put to the test as they navigate their conflicting motivations, shifting allegiances, and ancient magic.  
 
With the end of the tournament looming and Eala's threat growing, Fia must decide just how much she's willing to sacrifice to defeat her sister.