Blood Sacrifice - Guardians of Glede: Next Generation, #2

Tormented with guilt over the happenings in the Caves of Challenge, Prince Vantann Merripen watches over his siblings with a critical, judgmental and sometimes violent scrutiny. Prince Thomlin finally rebels and accidentally sets the course for an even more dangerous adventure than the one he and his brother endured in the Caves. Swept into a land that demonizes the second-born of twins, forbids magic, and is currently being terrorized by a coven of Nydiri, the twins very survival is threatened.
Any use of magic carries the penalty of death. Contact with the coven means the same, for the Nydiri are actively seeking twins to complete a powerful spell they intend to weave at the height of a mysterious orange moon. And elvin twins are especially prized.