The Sword, the Ring, and the Chalice Series by Deborah Chester

Dain, a half-elven boy, and Alexeika, brave daughter of the rebel leader, are the only ones who can save the kingdom from evil Crown Prince Gavril

A long-lost talismen helps a rebel princess and a half-elvin courtier realize the destiny that they share. 2nd in The Sword, the Ring, and the Chalice trilogy, following book one, The Sword

In the epic conclusion of the fantasy trilogy, the half-elven Dain, now the heir to the kingdom of Nether, joins his hated rival, Prince Gavril, in a perilous quest to find the Chalice of Eternal Life, hoping to use the magical relic to save the life of his beloved, Princess Pheresa, who has fallen victim to poison meant for Dain. Original.