Commander General Geon Grievous was a military leader in the Clone Wars and the Galactic Civil War whose career spanned thirty years, and was known for his tactical skill as well as droid-like visage. He served as the Commander General of the Imperial Army from 12 BBY until his death in 0 ABY. He was eventually defeated by Nero Nishi, who had extensively studied Grievious' warfare tactics and emulated him. His death preceded the Battle of Yavin by only a few months.