Most students of the arcane believe that all forms of magic is intimately tied to the Thorns and the Thicket. This belief is sometimes merged with the second most common theory: that arcane practice just hijacks free will. With the connection to the Thorns, it is possible t use power over those in order to affect magic itself. This is what the Thorns branch does. Using a tradition to pull on it, one can block effects created by others, enhance one's own, and other such things. It also grants some limited control over Thorns themselves, making it safer to practice the arcane and traverse the Thicket.