J N Lowther 
Darker Matter Book II — Wildfire [EPUB ebook] 

The Dyroshin fear that their most dreaded prophecy did not conclude when the Destroyer of Worlds and the Outlander clashed in an epic magical battle that destroyed the rift between worlds. But before its destruction, an immensely powerful being from a malign conquering race born of Black Metal found its way through the portal.Now the Five Lands are again under threat but this time from two foes of unimaginable might. There is only one weapon that may be effective, but it has been lost in antiquity and the very quest for its discovery is perilous and becomes a desperate fight for survival.