The R18 Division functioned as a mobile armored reconnaissance unit within the Separatist Droid Army throughout the duration of the Clone Wars; it was a division.
For their reconnaissance operations, and to bolster defenses of crucial Separatist holdings, the R18 Division employed Armored Assault Tanks alongside Single Trooper Aerial Platforms.
This division received orders to support the Y66 Division in its defensive duties, using B1-Series battle droids to operate the AATs. Nevertheless, during the second wave of the Battle of Christophsis, the Republic Army annihilated Y66's forces, prompting General Whorm Loathsom, who was inside an AAT, to command the R18 Division to withdraw. This retreat was to continue until massive force field generators were activated, providing a shield against the Republic's artillery cannons.