King Ars Primer+Constant Effects+Affinity_for_Dominance

Starting at 2nd level, a sovereign gains a bonus on Intimidate checks equal to 1/2 his class level. When the sovereign successfully uses Intimidate to influence the attitude of a creature in his collective, that creature will remain friendly towards the highlord for as long as they remain in the collective, and can be influenced to take actions that may endanger them.