Passel Koli was born in 2360 on Betazet as a member of the Second House of Betazet, to full Betazoid parents Holl and Kari Koli. She was interested in xenology at a young age, owing to her father's work as Diplomat for Betazet to the Federation. She was trained in her telepathic and emphatic powers at college, and she followed a year-long course on diplomatic conduct as a telepath. At age 22, Koli enrolled into Starfleet as an enlisted crewman. She served on Deep Space 9 for nearly 3 years as an assistant to the diplomatic corps there, fulfilling administration and secretarial work. In 2385, she was offered the job of Federation Vice-Ambassador to Bajor. She completed several diplomatic missions in 2385, until she was offered the position of Federation Ambassador at Starbase 98, near the Cardassian border. There, she met with the Tholians for the first time, and became interested in their culture. After two years serving as ambassador, she asked for a transfer to Star Station Esperance. She became intrigued by the Shoals. She spent almost 8 years on the station, acting as the connection between the Federation and the Colonial Coalition, while also coming into contact with the Klingon colonies and the Tholian diplomatic envoys. In 2396, she was promoted to Chief Petty Officer, and she requested a transfer to the USS Astraeus, where she entered in 239606.01 to become the ship's Ambassador. She took up her office at a small room near the Diplomatic Conference Offices on Deck 7.