Phillipa Matthias was a certified counselor serving in Starfleet in the late 24th century. In 2376, Lieutenant commander Matthias was assigned to starbase Deep Space 9 as the replacement for Ezri Dax. (DS9 novel: Twilight)

Phillipa was one eighth Vulcan in heritage. (DS9 - Worlds of Deep Space Nine novel: Andor: Paradigm)

Matthias was married to Chon Sibias, a Bajoran and had a son, Arios, and a daughter, Mireh. (DS9 - Mission Gamma novel: This Gray Spirit)

In 2376, Matthias was counseling the Andorian Shathrissia zh'Cheen (or "Thriss"), who was suffering from depression due to the absence of her bond-mate Thirishar ch'Thane, although she was unable to prevent Thriss committing suicide. (DS9 - Mission Gamma novels: This Gray Spirit, Cathedral)

Matthias was later invited to Andor to attend Thriss' sending (or funeral). While on Andor, Matthias was part of a strike team that liberated Andor's Federation Councillor, Charivretha zh'Thane, from a radical faction that held her hostage. (DS9 - Worlds of Deep Space Nine novel: Andor: Paradigm)

Phillipa was a capable counselor with a highly developed sense of professional ethics. She once refused to release details of her sessions with Shathrissia zh'Cheen to Colonel Kira Nerys and Lieutenant Ro Laren, unless they directly dealt with station security. (DS9 - Mission Gamma novel: This Gray Spirit)

Starbase Deep Space 9 personnel and residents
Station personnel	K. Adabwe • Ahzed • Aleco V. • Alle T. • Amran • T. Ane • N. Aponte • J. Bashir • Battes A. • S. Bowers • Cardok • Cenn D. • Chavez • Cryan • E. Dax • J. Dax • Devro • M. Eddington • Eddon • Etana K. • Gaysd T. • Girani S. • Goodman • Gordimer • Guerette • Hage • Hava • T. Jast • Jataq'qat • S. Jonsson • Kabo • Kahrimanis • Kelly • Kira N. • Kurn • C. Ling • P. Matthias • McCormick • McEwian • K. Merimark • Monyodin • Moru • I. Muckerheide • Munson • J. Si Naran • Nedani I. • Nguyen • Nog • Miles O'Brien • Occino • Odo • D. Parks • Pertwee • Phongsit • G. Primmin • Redac • K. Richter • Ro L. • Rom • G. Roness • Sanger • Selzner • J. Senkowski • Setrin Y. • Shul T. • B.L. Sisko • N. Sthili • M. Strang • S. Tarses • P. Tenmei • Terek • T. ch'Thane • Tolland • M. Tomson • T'Peyn • Trulli • E. Vaughn • Vu K. • Wasa G. • Wayeh S. • D. Wilkens • Worf • Woros K.
Station residents	Broik • Chram • Conpap • Elvim • Frool • Gann • E. Garak • Grehm • Grimp • Jas-qal • Kaga • Leeta • Modo • Morn • Nog • Keiko O'Brien • Molly O'Brien • Kirayoshi O'Brien • Quark • Rom • J. Sisko • Sorv • Taran'atar • Tora Z. • Treir • Vissh • K. Yates • Yelsi