Erisi Dlarit is a Thyferran, a member of one of the powerful families that control her planet’s bacta production, and a pilot of Rogue Squadron under the callsign Rogue Eight. She is one of the original intake in Rogue Squadron (Bantam Spectra, 1996) and, as the series reveals, its traitor.
Stackpole plays it fair. Erisi is competent, charming and openly interested in Corran Horn, and the reader is given every reason to like her before the mechanism becomes visible. The betrayal is not a personality twist; it is a commercial one. Thyferra’s bacta cartels have an interest in who governs the galaxy, and Erisi is her family’s instrument rather than a psychopath in a flight suit.
That makes her the hinge of the series’ best storyline. The Krytos virus is engineered to kill non-humans on Coruscant, and the only treatment is bacta — so a plague becomes a market, and the New Republic finds itself hostage to a planet it has no lawful way to coerce. The Bacta War (Bantam Spectra, 1997) is the payoff: a squadron resigning its commissions to fight a war the government cannot admit to.
Her squadron-mate Bror Jace comes from the same world and the same industry and lands on the opposite side of it, which is Stackpole refusing the easy reading. Erisi is Star Wars Legends.