The Toll-Man was the guardian of the bridge across the Bottomless Pit that led to the House of Foryx.
Septimus Heap, Jenna Heap, and O. Beetle Beetle must get past him to reach the House of Foryx. He asked them to give him valuables, like Jenna's circlet. He was Inhabited by a Thing that was Summoned and Released by Merrin Meredith, and tried to kill Septimus while Inhabited. Septimus pushed the Toll-Man into the Bottomless Pit, thus killing both the Thing and the Toll-Man.
It was said that the Toll-Man was never a pleasant character, even before he was Inhabited by the Thing.