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The Qowat Milat were an order of Romulan warrior nuns introduced in the Star Trek: Picard episode Absolute Candor.
The Qowat Milat practiced The Way of Absolute Candor - total communication of emotion without filters. They highly prized truth, referring to their homes as houses of truth. Their commitment to truth ran totally counter to mainstream Romulan society. The order was exclusively female - while men could train in their ways they could never truly become members of the order.
Seen by some as assassins, Qowat Milat sisters could not be hired but would grant assistance to those deemed worthy. Individual Qowat Milat could bind themselves to a cause they deemed worthy - usually a lost cause - as a qalankhkai.
During the evacuation of Romulus in 2385, the order provided invaluable assistance to Admiral Picard in his efforts to evacuate the homeworld before their sun went supernova. After the rogue synth attack on Mars the Federation abandoned the evacuation effort. Feeling that Starfleet betrayed him and the Romulans, Picard retired from the fleet and returned home to France.
Meanwhile the Qowat Milat helped keep the peace on Vashti which was a major refugee center of about 250,000 Romulans. They raised the orphan Elnor and trained him in their ways.
Picard returned in 2399 to seek the order's assistance. Their leader Zani suggested that Picard ask Elnor to join them as qalankhkai. Initially refusing, Elnor later decided to help Picard after all and bound himself to Picard's side as qalankhkai.