The god of dreams was able to gain the help of the god of seers and the god of fate. This made the job of finding a needle in a haystack a feasible prospect for him.
The god of seers gave him a subordinate god to help him search for Legion, while the god of fate pointed him in the right direction to look for Legion by telling him to start searching.
The god of fate couldn't find Legion because of the divine abilities of their undying pathway, but she could find, among the infinite possibilities of the future, the one possibility where the god of dreams found Legion.
It is a fact that if the god of dreams searched every inch of the world for an infinite amount of time, he would find Legion because the possibility of finding Legion is not zero. It is just that the god of dreams can find Legion in one minute or a thousand years.
