Marshal Undead (Su) [Subjugation]: Once a day, a bone tyrant master can call undead to gather towards it. This is resolved like a use of the tyrant's Subjugate Undead ability (see below) that can affect any undead within 20 miles of the master except for other bone tyrants. Marshal Undead does not require line of effect or line of sight. Affected undead start walking towards the bone tyrant master, taking the most direct route available. A marshaled undead will try to move around or break through obstacles, and will attack creatures to threaten or obstruct them. If the Subjugate Undead check had a "rebuke" result, the undead will walk towards the master for 1 hour and then revert to its normal behavior; undead Subjugated by a "command" result will keep walking until they are destroyed or a bone tyrant instructs them to stop. A cleric may channeling channeling positive energy or negative energy to dispel a Marshal Undead effect. This follows the "Dispelling Turning" rules for an evil cleric except there are no alignment restrictions.
...come to think of it, I'd also add
A bone tyrant master can marshal up to X Hit Dice of undead at any one time. These undead count towards its Subjugate Undead Hit Dice limits. A bone tyrant (master or minion) can determine the location of its marshaled undead (as per the locate creature) spell) as an at-will ability.
