Sprig is a character from the Grey Griffins, written by Derek Benz

Derek Benz

Derek Benz is an American author of fantasy fiction for children and co-author of the popular Grey Griffins, originally published by Scholastic, Inc. Benz works in collaboration with J. S...

 and J. S. Lewis. Sprig is a mysterious shape-shifting spriggan

Spriggan

Spriggans are legendary creatures known from Cornish faery lore. They are particular to West Penwith in Cornwall.-Spriggans in folklore:Spriggans were depicted as grotesquely ugly, and were said to be found at old ruins and barrows guarding buried treasure and generally acting as fairy bodyguards....

, whose motives are unknown. Her early history is unclear, apart from the fact that she served as a handmaiden of Titania, the Faerie Queen, until the spriggan stole her mistress' Jewel. For her crime, she was hunted across the Shadowlands and subsequently on Earth as well. At some point she was captured and imprisoned within the Codex Spiritus and remained there for thousands of years until finally freed by Max Sumner.

It is confirmed in The Fall of the Templar

The Fall of the Templar

The Fall of the Templar is the third volume of the Grey Griffins series written by American authors Derek Benz and J. S. Lewis, and published by Orchard Books, an imprint of Scholastic Press...

that Sprig is Max's Bounder, attached to him as closely as his own soul.