Voyage to Morticas — Paul Collins

Book Five in the exciting collaboration between Paul Collins and Sean McMullen, two of Australia's most popular fantasy authors.
Although Dantar is able to shapeshift into dragon form, he still thinks like a rebellious teenager. His sister Velza has been given the ultimate gift by the dragons of Dracondas â€" the mind of a dragon. Now they must combine their gifts to stop the most powerful warlock of all time from casting his doomsday spell.