Irina is the daughter of Gwyn Reinford, who was the chairman of the Reinford Group. She followed her father's work greatly, eventually becoming a workaholic, completely centered on the growth of the company. Sometime later, she eventually met and married Franz and had a daughter, Alisa. It is implied that she enjoyed both her work and family life, as Alisa states that her family was genuinely happy when her father was still alive.
In S.1196, Franz was possessed by Ishmelga, who had implanted a manifestation of Alberich in him. F. Novartis had taken interest in Franz's resources and had sent the Enforcer Kreuger to visit him in advance. Alberich fully manifested and attacked Kreuger, the ensuing fight resulted in Franz apparently dying and Kreuger being seriously wounded. Irina, who soon discovered Kreuger, decided to help the girl, giving her the name Sharon and offering her a position as the family maid until Franz returned.
After the incident, she became fully enveloped in her corporate work. When the Imperial government commissioned Reinford Group to build new railway guns at Garrelia Fortress, her father Gwyn, who was the chairman at the time, began to oppose the project, realizing the damage they could do. In order to push the growth of the company to its limits, she crossed the boundaries of morality and ventured into the production of weapons of mass destruction. She forced her father to resign by gaining the support of the shareholders behind his back before occupying the position herself. This severely damaged their relationship, but she did occasionally contact him when it was in her interest. She continued to built on her father's legacy by introducing a new self-supporting accounting system of the four divisions of the company to make them even more profitable.
Irina served as one of the directors on the board of Thors Military Academy, serving as a technological representative due to the company producing the orbal staff and the ARCUS II units which were in use there. Due to this, she eventually learned of her daughter's enrollment into the academy. She decided to support her daughter, at first by ensuring that she had enough mira to pay for expenses. Sometime after Class VII's second field study, she sent Sharon to take care of Alisa.
During the Erebonian Civil War, Heidel Rogner seized Reinford Group to support the nobility's war effort against the Imperial government. Heidel kidnapped Irina and held her hostage on the Eisengraf, claiming the the populace that she was ill and that he would be taking the position temporarily. Irina was rescued by both Class VII and Sharon, where she assisted Class VII by disabling the building's security for them. Upon confronting Heidel, she was impressed by his cunning, but was angered at his arrogance in claiming her family home as his own, beating him up in front of Class VII.
She was eventually able to ease the tensions with her daughter following the end of the war.
One and a half year later, however, things were turned upside down for the Reinfords when her husband Franz revealed himself to be very well alive under the guise of 'Black Alberich', head of the Black Workshop. Due to this, Sharon resumed her duties as one of Ouroboros' Enforcers and dismissed the name of 'Sharon' once given to her by Irina.
Due to the group's position with the Imperial government, when Erebonia declared war on Calvard for the attempted assassination of Eugent III, Irina complied with their request to develop weapons of war, such as the Zauber Soldats and Gargantua-class airships. When Alberich deployed a Leviathan unit to stop Class VII from starting the second Rivalry prematurely, it went berserk and attempted to target her and Schmidt, who were simply spectators. The incident caused Irina to consider Alberich was not the husband she knew and she offered Sharon her position back as family maid.
Trails of Cold Steel I, II, III, and IV