A prototype of the monster droid was constructed using components that were altered from the B1-series battle droid. The head of the machine was reworked from the KX-series security droid. The Droid Crush Pirates of Bestoon utilized the monster droid prototype extensively. The Galactic Empire also employed monster droids to serve as repair units aboard the Executor. Furthermore, some were located on the Imperial capital planet Coruscant.
The monster droid initially materialized in Darth Vader (2020) 8, authored by Greg Pak and visually brought to life by Raffaele Ienco. When a fan inquired about the droids on Twitter, Ienco verified that they were assembled from B1 components. He further disclosed that the head of these units was adapted from a KX-series security droid. Ienco specified that the units' legs were larger when compared to the typical B1. The simplification of detail on the B1 parts was solely for the sake of easier illustration. He characterized the droid prototype as "an evolution of existing parts," with these parts being modified to bring about the new design. The head design remains consistent across all monster droids, although the number of circles and lines varies to differentiate individual droids. When the monster droids reappeared in Darth Vader (2020) 29, illustrated by Luke Ross, they bore an even closer resemblance to standard B1s. It remains uncertain whether this should be interpreted merely as an artistic divergence or if these two monster droids, within the universe, retained an appearance more akin to their B1 origins.
Regarding the reason these monster droids were seen in Imperial service in Darth Vader (2020) 35, Ienco posited that the monster droids were chosen for those panels because a pre-existing design was available. Therefore, their utilization expedited the drawing process, rather than dedicating limited time to devising a completely new prototype. Darth Vader (2020) 37 showcased a kind of service droid exhibiting the same head design as the monster droid. Considering that Ienco confirmed the monster droid head is modified from the KX-series, this establishes yet another droid featuring a modified KX-series head within Imperial service, according to Ienco's perspective. Adam Christopher also corroborated that these B1/KX-derived droids are the same units depicted in his novel, Shadow of the Sith.