The Exiled Heir — Jonathan French

In this epic fantasy from the acclaimed author of The Grey Bastards, a man and his fae allies confront Goblins seeking to restore their race to power.
 
Locked in an eternal Autumn, Airlann, the Source Isle of Magic, is dying. Nearly a millennium earlier, the last of the Goblin Kings were assassinated. Now a fanatical army of Goblins known as the Red Caps are determined to bring their bloodline back to the throne via an heir whose identity is a deeply guarded secret.
 
Padric, a human cast aside as cursed by his own people, travels alongside the alluring piskie Rosheen, his lifelong friend. As the Red Caps wage war, Padric and Rosheen find themselves in midst of the battle, having allied themselves with the unlikeliest of creatures: Deglan Loamtoes, a healer gnome whose cynicism is rivaled only by his quick wit, and Pocket, an orphaned changeling fostered by the avian Knights of the Valiant Spur. 
 
Soon this ragtag posse of wayfarers is confronting skin-changers, bloodthirsty marauders, and fire-crazed fanatics -- determined to discover the true identity of the long-lost heir before the Red Caps release forces powerful enough to destroy Airlann once and for all. But is this band of unlikely heroes strong enough to stand against the descendant of the dreadful Goblin Kings?
 
“An addictively readable -- and undeniably cool -- fantasy masterwork.” -- Kirkus Reviews (starred review) on The Grey Bastards