Throne of Deceit — Richard Fierce

Two souls, one destiny.
Their royal parents assassinated, two young siblings are separated and hidden to protect their future and the future of their kingdom. Only when their adoptive families are murdered do they discover the truth of their heritage. Now it is time to reclaim what is theirs.
But to do that, they will need an army - and magic. With many interested in their royal roots, they must decide who can be trusted ... and who is trying to kill them.
Throne of Deceit is the first book in the series Dragons of Isentol, a tale of dragons, magic, and a growing rebellion against tyranny.