At last we see the full picture. Oldest can be anywhere inside the black circle. This is his search area, the portion of the zone that we have to examine in order to be sure of finding him.
Oldest's search area is enormous. It has a diameter of more than 20,000 units. If you stood at the center of it in broad daylight, with your clip range set to far, you could see mobs in only 12% of it.
I'd like to show a screenshot that illustrates a distance of 20,000 units, but it's impossible because nothing in the game is visible at that range. The best I can do is show you what the building looks like when it's half that far away. In other words, if the character in the next screenshot was standing at the center of Oldest's search area, the building would be on the outer rim: