In Firiona Vie and the Tower of Frozen Shadow: Appeared briefly in these zones as part one-time-per-server events in the weeks leading up to the Dragons of Norrath expansion (January 2005).
In Bloody Kithicor: Located in the Army of Light headquarters (western side of the zone outside the Highpass zone).
In Bloody Kithicor (Raid): Part of the "Bloody Kithicor" raid expedition (see this quest entry for event information).
In Discord Tower: Part of the Stasis event (see this quest entry for event information). For event loot, see the chest which spawns after successful completion.
In Al'Kabor's Nightmare: Located in the ruins of Felwithe at approximately -400, -5000.
In The Other Side of the Rift: Firiona Vie plays a part in sending Lady Lendiniara back home.
In Katta Castrum: Deluge: Firiona Vie (click for map image) is found on the main floor of the zone-in temple.
In the Combine Dredge: Firiona Vie (click for map image) is found at the zone-in as well as in the southeastern corner of the zone. She also appears in the mission "Deep Lies the Snow" (see this quest entry for details).
In Arx Mentis: Firiona Vie (click for map image) is found at the zone-in as well as the top floor of the citadel. She also appears in the missions "All Rivers Lead to the Sea" (see this quest entry for details), "The Cost of Balance" (see this quest entry for details), and "Confronting Calix" (see this quest entry for details). She also appears throughout the raid zone (see this quest entry for the raid expedition overview).