The Sambac Crystal and The Stolen Kingdom by Paul Russell Parker III. Book 1 of the Crystals of the Enchantment Tree series.
Calevallin is in turmoil. Subjects are disappearing and whispers of strange, new monsters are spreading throughout the Kingdom. Even worse, the King and Queen seem to be oblivious to the new danger at hand.
Not Drey though. Drey and her brother Sully, are quietly training to defend themselves in the forest near their family’s cottage. Even with years of training, nothing will prepare them for the looming war when dark forces are seemingly given free rein in the Kingdom.
Dark forces led by the King’s closest advisor; Jaike. Jaike, the feared man in the shadows who holds the Sambac Crystal.