Mistress of the Winter Constellations
Mistress of the Winter Constellations was a hereditary title held by a senior female member of House Tendi, one of the most powerful families in the Orion Syndicate. It evoked substantial respect and fear from ordinary Orions, as the Mistress was inevitably a fearsome warrior and battle commander. Many Orions knew the current Mistress' identity, though this was not universal. (LD: "Something Borrowed, Something Green", "Dos Cerritos")
Astrea Tendi was the Mistress during the mid-23rd century. (SNW: "Those Old Scientists")
D'Vana Tendi was the Mistress during the late 24th century. She continued to hold this title even after she left the Syndicate to join Starfleet. D'Vana leveraged the prospect of the Mistress returning to House Tendi to bargain with her sister D'Erika for a battleship in 2381. (LD: "We'll Always Have Tom Paris", "Old Friends, New Planets")
Under Orion law, the Mistress was required to personally train her successor for the first fourteen years of her life. For this reason, D'Erika concealed her pregnancy from D'Vana in 2382, knowing that her child would be the next Mistress but that D'Vana desired to return to Starfleet. (LD: "Shades of Green")