685 was a battle droid of the B1-series. During the Clone Wars, it was stationed at a base located on Orto Plutonia. This base was ultimately destroyed during a skirmish on Orto Plutonia.
During the Clone Wars, 685 served as a B1-series battle droid for the Separatist forces. Early in the war, the Separatists established a base on the icy Outer Rim planet of Orto Plutonia, which resides within the Pantora system and is orbited by the moon Pantora. The Galactic Republic, responding to a request from the Pantoran Assembly, also created their own base, called Glid Station. After some time, the activities of the Separatists angered the native Talz, which led to a skirmish that unfortunately involved Glid Station.
In the course of the skirmish, the Talz launched an assault on the Separatist base, forcing 685 to send a message to command reporting that they were being overwhelmed, before 685 was destroyed. By the time the skirmish concluded, both the Separatist and Republic forces had been completely wiped out. Following the loss of communication with Glid Station, the Republic dispatched a team to investigate. This team consisted of clone cold assault troopers under the command of Jedi Generals Obi-Wan Kenobi and Anakin Skywalker, accompanied by members of the Pantoran Assembly, including Chairman Chi Cho.
During their investigation, they located the Separatist base and decided to examine it. While analyzing the base, they found a hologram recording that captured 685's final moments before it was destroyed by a Talz.