One had to understand that an Upper Realm, from one end to another, is approximately over one million light-years in distance. It was nearly ten thousand times bigger than a Lower Realm. Even forty-eight Lower Realms failed to compare to a single Upper Realm.
An Immortal Emperor may never exit the Upper Realm they were born in their entire lives, as it could take nearly fifteen thousand years for them to travel from one end to another without a single stop.
Distance and speed were just one factor. The danger one would face while traversing nearly five quintillion kilometers wasn't something that they could tackle.
To put that in perspective, it was an insane nineteen-digit number: 5,000,000,000,000,000,000!
There would be plenty of adversities on the way for them to die without crossing even ten percent of the distance.
