Originally this forlorn looking machine was merely a construction/maintenance mech. But eventually the city that it was stationed it was vacated after conditions became too hazardous for human life. Pollution, degradation, acid rain, the entire city was forcibly evacuated, then quarantined until the federal government could allocate the funds to either restore or demolish the city.

Unknown to almost everyone, a few of the maintenance units remained online, and despite the fact that their operators were no longer there, continued their work as per their programming.. cleaning, filtering, planting, restoring.. One by one, the units fell to lack of repair and parts, some breaking down in the middle of their work. A couple, out of necessity, started to scavenge for parts and downloaded what repair manuals they could.

This guy is the last of the maintenance units left online in what was left of the city. The others worked until they could no longer move. It was their efforts that allowed him to learn how to keep himself online despite the lack of care. Traveling around the city, he would take what parts he could use from other robots that were either shut down or destroyed in the riots preceding the forced evacuation.

Effort and this patchwork self-repair have been a leading factor in The Caretaker's specific contribution; The only known foliage within 20 miles of the center of the city. One of the parks that he came across had some vestiges of life left in it's barren soils... He went to work, restoring the park bit by bit, year by year...