Qin Feng had employed his escape technique to travel downward, and because the Rainbow Bridge directly penetrated space, the journey from the Midgard World to the Netherworld Death Kingdom of the lower realm didn't actually take much time. This was the unique feature of the Rainbow Bridge.
Otherwise, given the towering height of the World Tree and the vast distance separating the three worlds, even if Qin Feng had flown nonstop, it would have taken days to traverse such a lengthy distance.
The Valkyrie girl warriors of the Divine Country often traveled between the two realms to select the souls of warriors from the battlefields. If it took them several days just to cross the Rainbow Bridge, by the time they descended from the Divine Country, the battlefields would likely have been cleared, leaving no souls for them to choose.
