The Dragon and the Faerie - YA fantasy by Roland Capalbo

Sixteen-year-old Andy has an inhuman appetite for adventure. He ignores the dangers and potential victims of his recklessness, until his sister is lost through a portal to another world. Who knew a ruined, condemned castle perched on an island in the Hudson River was dangerous? Seemed more like an adventurer's dream instead of a nightmare.

Andy follows his sister through the portal, landing himself into his own special kind of trouble. Unknowing, Andy was lured through the gateway by the demon sorcerer Devon, who plans to use Andy as portal doorstop, allowing himself to crossover and dominate our world.
With the help of the wise wizard Loki, Andy escapes, but learns his only way home can only happen with the death of Devon. Oh, and to make matters more fun then they already are (insert sarcastic tone), Andy is no longer human...

A world full of magic, wizards, gods and a goddess. Faeries with incredible abilities fight alongside humans and dragons. Hero's are born and quests undertaken. All this and more await you in the land of Vasara.