In his Google Docs entry, he is barely described. Besides, things have changed since then, so it wouldn't hurt to update the one entity that still remains connected to their physical reference.
Scrapbot originated from a moon robot lego-set my best friend got me for my birthday long, long ago. Since then, a lot has happened to that poor bot, including the loss of his wheel legs, and the building of some different legs instead, becoming Scrapbot, in the time when my legos were contained in a bucket. Eventually, Scrapbot lost his legs and head, and was fused with the headless remains of the Green Ninja dragon from the Lego Ninjago Movie, creating a headless centaur. Scrapbot now sits upon my shelf with my other big lego creations, having gained new allies.
Physical description of Scrapbot's original incarnation will be difficult due to a lacking of pictures, thus shortening this entry considerably.
Scrapbot's area, the Scrapden, is something of a time-anomaly, the Prime and Decayed variations of Scrapbot simultaneously existing, sharing the Arena, each taking up roughly a half. Both share similar interests, to find take care of scrapped or ruined entities and repurpose them, as that was why Scrapbot existed in the first place. Their twin hostility is primarily directed at those who waste without care, as the Cave System Junkyard partially connects to their arenas, allowing them to find stuff that's been thrown away.
Somewhere within the arena exists the original Moonrover as well.
The Three each have their own names to differentiate between them, Moonrover for the pure, Scrapbot for the Prime, and Rotdragon for the decayed. Each has their own sectors, with Scrapbot and Rotdragon being far more prominent.
The three are somewhat close friends, though Moonrover remains horrified that he is doomed to a horrible fate.