Tuck this under your Fate card.
You are the Lord of Cluster 5.
Rivals with a Loyal city or Flagship in Cluster 5 are your Vassals in Cluster 5.
You may tax any cities in Cluster 5, ignoring control. (Take Captives if you tax cities of your Vassals!)
If you harm a Vassal in Cluster 5, or a Vassal harms you in Cluster 5, the harming player Provokes Outrage with all cities in Cluster 5.
Act: 2
A: No. A Regent Lord is bound by the Truce law when taxing a Regent Vassal city under Imperial control, and bound by Closed Economy when taxing an Outlaw Vassal city under Imperial control. An Outlaw Lord can always tax Vassal cities regardless of Empire control.