Dr. John Bonsaint was the older brother of Sheila Bonsaint.
He treated the patient N. for obsessive-compulsions related to what Bonsaint believes to be delusions. After he learns of N.'s fate, he journies to Ackerman's Field, the site that precipitated N.'s neurosis, and begins to suffer the same effects as his late patient. At the Field, he also finds a key to the locked chain that bars the road leading to the Field, and thereby inherits the responsibility of maintaining the stone circle it contains. As Bonsaint becomes consumed with the same symptoms that brought N. to him in the first place, Bonsaint ultimately follows in his patient's footsteps when he falls to his death from the Bale Road Bridge.