The shadow dragons - James A Owen

The Caretakers of the Imaginarium Geographica are at war. The last stones from the Keep of Time are falling, and, at the request of an old enemy, a new tower is being built in our world. The old enemy is the Winter King's Shadow, and he wields a terrible weapon - the Spear of Destiny - which can be used to command the shadows of anyone it touches… including the protectors of the Archipelago, the dragons.
The Shadow King returns to the Archipelago using the ship, the Iron Dragon, and enlists an unstoppable army of Dragon Shadows…
While WWII rages in our world, all the caretakers, both past and present, must come together to save the Archipelago. All hope lies with a small group of companions, along with mythical knight, Don Quixote, who must sail beyond the very ends of the Archipelago in search of a broken sword, and the only being alive who can repair it: a scholar, who, once upon a time, was called Madoc.