Guardian Sentinel

The Guardian was a Forerunner Sentinel located at The Ark. They fill the Forerunner's role of Mobile Full-Service Construction Platforms, and are used to extract raw materials from The Source, and process them whilst transporting them to the work site, the site being a Halo. They bare a slight resemblence to Compilers from Marathon, a previous Bungie game. They were set to be seen in Halo 3, but were removed, and featured in The Art of Halo 3.