The entity known as the Overseer was a Rakatan guardian droid that existed circa 30,000 BBY, during the pinnacle of the Infinite Empire.
This droid's purpose was to oversee the construction of a temple located on the planet Dantooine. Its duties included ensuring the temple's construction adhered to the specified plans and maintaining order among the slaves working on the project. Consequently, it was programmed to communicate in the ancient Rakata language, along with the languages spoken by the Infinite Empire's enslaved populations, such as ancient Selkath and Tusken.
Following the project's completion and the subsequent execution of all the slaves involved, the Rakata reprogrammed the Overseer. It was then stationed at the site to disseminate information about the Star Forge to any Rakata who sought it. However, this function never came into use, as no Rakata ever made their way back to the temple to utilize the Star Map contained within.
Many millennia later, the two Jedi, Revan and Malak, encountered the Overseer during the Mandalorian Wars. They had ventured into the temple, which was by then reduced to ruins, in pursuit of knowledge about the Star Forge to fuel their ambitions of conquest. The droid explained that to gain access to the temple's inner sanctum, they needed to demonstrate their "worthiness" by proving their understanding of the ancient Rakata's reasoning. They succeeded in this task, commencing their galactic journey to locate other Star Maps and initiating their transformation into Darth Revan and Darth Malak.
In 3956 BBY, Revan, now suffering from amnesia, returned to the Rakatan ruins accompanied by Bastila Shan and once again encountered the Overseer. The droid, showing no sign of recognizing the former Sith Lord, reiterated the objective to which it was assigned to the temple's visitors. They also successfully completed the objective, uncovering the method by which Revan and Malak had originally discovered the location of the Star Forge.