Nickolai of the North - Lucy Daniel-Raby

Nickolai is an elf, sole survivor of the wicked Magda's onslaught on the magical elf kingdom. Nick carries with him the only remaining Light Fairy in the world, his constant companion Elvina.

Brought up by a human couple in the distant north, Nickolai knows that there is something different about him. Little does he realise that he was not born to humans, but rescued from the evil Magda by flying reindeer. And Magda continues to construct her evil empire, the city of Doransk. But when she starts to steal children's youth in order to regain her own beauty, Nick and Elvina must travel north, with the help of their friends, to foil her plans ...

And so at the end of the book, Nickolai makes a pledge to return once every year at the time of winter solstice, to give presents to the world.