The IG-86 sentinel droid, also referenced as the IG-86 assassin droid or the IG-86 sentry droid, represented a specific model of assassin droid that was produced by Holowan Mechanicals.
The IG-86 units were created as an enhanced version of the standard battle droid, and they served within the InterGalactic Banking Clan's Collections and Security Division. Their popularity also extended to gangsters, such as Ziro the Hutt. Many IG-86 droids in Ziro's possession displayed the Black Sun symbol, mirroring their master. KRONOS-327 was one such droid. They were commonly deployed throughout the Clone Wars, serving both independent entities and the Confederacy of Independent Systems.
Gha Nachkt, a Trandoshan junker, maintained several IG-86 droids aboard his ship, known as the Vulture's Claw. After Nachkt salvaged the astromech droid R2-D2 following the battle, Anakin Skywalker and Ahsoka Tano boarded the vessel in search of him. During their search, they encountered and engaged with two IG-86 sentinel droids.
During the capture of the Senate Building, Cad Bane commanded a group that included three of these droids. Anakin Skywalker, lacking his lightsaber at the time, managed to destroy one of the droids by using its own blaster rifle as a club. HELIOS-3D and HELIOS-3E aided Bane in various operations.