Picus the Thief — Robin Bennett

Picus has a lot of powerful enemies. His aristocratic parents have disowned him for supposedly being a coward; the violent vampire, Raben, is after him to exact revenge for theft; the faie, Queen Mab (aka the Tooth Fairy), wants his teeth; and the vampire Eltern want him to steal the sacred sword of Exkylipyr for them, or else lock him up in a dungeon. 

In the course of avoiding Raben and Mab, he goes to Angleland, befriends the humans and the witch Ambrosias, and manages to win (not steal) the sword he was sent to pinch. 

But on his return he faces the ultimate test: to keep Exkylipyr from his family and thereby prevent her from starting a civil war amongst the vampires. 

Small Vampires is essentially an Arthurian grail quest trilogy for young adults, set amongst vampires and other fantastical creatures in the Hidden Kingdom. After a period of several millennia, this fantasy world is beginning to clash with the human world, with supernatural consequences.

Start following Picus's adventures and visit the magical world of the Hidden Kingdom in the first book in the Small Vampires series.