Claus: Legend of the Fat Man (Claus Universe, Band 1)

In the early 1800s, Nicholas, Jessica, and Jon Santa attempt the first human trek to the North Pole and stumble upon an ancient race of people left over from the Ice Age. They are short, fat, and hairy. They slide across the ice on scaly soles and carve their homes in the ice that floats on the Arctic Ocean. The elven are adapted to life in the extreme cold. They are as wise as they are ancient.
Their scientific advancements have yielded great inventions - time-stopping devices and gravitational spheres that build living snowmen and genetically-modified reindeer that leap great distances. They've even unlocked the secrets to aging. For 40,000 years, they have lived in peace.
Until now.
An elven known as The Cold One has divided his people. He's tired of their seclusion and wants to conquer the world. Only one elven stands between The Cold One and total chaos. He's white-bearded and red-coated. The Santa family will help him stop The Cold One. They will come to the aid of a legendary elven known as...Claus.