The Ostrini were people that lived in the UIR nation of the Ostri Republic.
Several Ostrini citizens were stationed at Aspho Point when Operation: Leveler began, which led to the killing and capture of the Ostrini staffers. Several dozen Ostrini citizens and UIR soldiers were killed during Operation Leveler during the destruction of Osigcor and the leveling of Bonbourg and Berephus.
After the fall of the UIR and second era of peace was established under the COG, the city of Bonbourg was rebuilt. When the Locust attacked on E-Day, Bonbourg, along with the rest of Ostri, was hit. It took over a year for Premier Deschenko to lose Ostri and over 20 brigades of Gears. The Ostrini people tried to cross the border into Pelles or where killed by the advancing Locust. After Chairman Prescott launched the Hammer of Dawn Strikes, both the nations of Pelles and Ostri were destroyed.