An Imperial Shard of considerable experience, Ider Firenz was a veteran of Brankfall, Tochi, and Ottomas. This so-called "unholy trinity" of operations took place amidst events the Imperial Combine would later come to refer to as the Trinity Crisis.
Due to her extensive experience and broad skill set, Firenz was assigned to evaluate the newly graduated counterpart Mostrum Appatine as he transitioned from his CAGA duties on a probationary assessment period. The pair were sent to offer close protection services to Proconsul Chellis Bel-Osanda, and her guest Ambassador Ohl Ain of the Lem Bataan Confederation, during the ambassador's diplomatic visit to Fengrir (→SFTD).
During that mission Firenz and Appatine were attacked by renegade ex-counterpart Maber Castigon. It is evident from the encounter that Firenz was somehow linked to the events which resulted in Castigon being sent to prison, and it is more than likely that she contributed to that outcome. Believing that Castigon was making an attempt on Ambassador Ain's life, Firenz placed herself in harm's way. She was shot in the head by Castigon and died immediately (→SFTD).