The initial Battle of Plagen unfolded on the planet known as Plagen, pitting the forces of the Confederacy of Independent Systems against those of the Galactic Republic. This confrontation marked one of the many conflicts within the larger Clone Wars, a war that spanned the years 22 BBY to 19 BBY. Leading up to the battle, the Confederate General Piar Nagelsa met his death at the hands of a T-series tactical droid within his own ranks, a consequence of the common issues droids experienced when taking orders from organic commanders. Subsequently, the droid seized control, discarding Naglesa's planned strategy and ultimately guiding the Confederate forces to victory in the engagement.
The initial reference to the First Battle of Plagen appeared in the 2012 publication, The Essential Guide to Warfare. This comprehensive Guide explored the various wars and battles of the Star Wars galaxy, and was authored by Jason Fry together with Paul R. Urquhart. Despite being designated as the "First Battle of Plagen," no additional battles on the world have been officially documented.