The Talisman Series by Brett Salter Wiki

Clay Andreas- Appears in all books but book 2. When the reader first meets Clay, he is one of Rome's hackey-sack buddies who seems to ultimately have his back. However, Clay's human form is just the product of a concealment spell placed on him by his Synergist Knight.  In reality, he is an Earth dragon that has completed The Great Synergy with shamed Rider family member, Jericho Rider. Together, they want to team up with Julian on his quest to defend the Earth against the Darkbrands, but after a Nocturn possesses Jericho, Clay is forced to use his Earth dragon abilities to attack the boys. Once the Nocturn is exercised, Clay and Jericho make lifelong pledges to support and defend The Alliance. Like all dragons who have used The Great Synergy, the concealment spell on Clay can be removed at his choosing allowing him to reveal his true dragon form. This usually happens either when it is time to fight or when it is time to eat.

The Great Synergy: He is bound to Jericho Rider by Hatshepsut’s Tooth. This allows his dragon heart to be completed, but it also links their souls together for life.

Abilities: Clay is an Earth dragon which is, on average, the most massive of the dragon clans.  They are flightless, but have thick, tough hides covered by dark-brown rock scales that cannot be penetrated.  Most have spiral horns and shelled foreheads, which can be used for both offensive and defensive weaponry.  Most Earth dragons have amiable personalities except when they are thrown into battle. Their size and warrior savagery alone make them some of the best tanks in the dragon ranks.

Trivia: Clay's first and last names are references to Georgia red clay and the San Andreas Fault respectively. Both are examples of terrestrial phenomenon.

Clay is constantly seen snacking throughout the books, though his favorite snack is reportedly jellybeans