|Location||South west of Haven and the Greenwoods River in Tortall|
|Bodies of water|
|Leader/Governor|| Wyldon of Cavall (the district commander)|
Vanget haMinch (General of the Northern Armies)
|Residents|| Harailt of Aili|
Owen of Jesslaw
|Affiliation||Tortallan armed forces|
|Head of State|
|Tortallan Universe place|
|Only Appearance||Lady Knight|
Fort Mastiff was a fortified command post used by the Tortallan armed forces during the Scanran War. It was located about 50 miles northeast of Fort Steadfast, a little less than 50 miles west of Haven, about 100 miles west of Fort Giantkiller, and about 200 miles southwest of Northwatch Fortress.
During the Scanran War, Fort Mastiff became a main command post of the armed forces against Scanra and Maggur Rathhausak. It was commanded by Lord Wyldon of Cavall, a knight. Prior to commanding Fort Mastiff, Wyldon was in command at Fort Giantkiller.
After Stenmun Kinslayer and a bunch of Scanran warriors and killing devices attacked Haven, Lord Wyldon ordered Kel to return to Mastiff after burying the dead at Haven, as he believed the attack on the refugee camp was a diversion, and that the Scanrans' main goal was to take Mastiff. It turned out that Lord Wyldon was wrong, and that Stenmun's main goal was to take 200 children to Blayce the Gallan to be turned into killing devices.
By late April, Mastiff is run tidily due to the leadership of Wyldon of Cavall. It had a double set of log walls, the latter of which was 20 ft in the air. Mastiff housed three whole companies of soldiers, and had mages, healers, hedgewitches, and clerks.