Senior Warrior was a rank within the Chiss Ascendancy's Chiss Expansionary Defense Fleet. This military rank sat in the hierarchy between Mid Warrior and lieutenant. The Chiss officer Yopring possessed this rank circa 18 BBY while serving on the Nightdragon man-of-war named Vigilant in the Expansionary Defense Fleet.
The 2021 novel Thrawn Ascendancy: Greater Good, the second book in Star Wars: The Ascendancy Trilogy by Timothy Zahn, marked the initial appearance of the Senior Warrior rank.