Sacrificing the "high popularity character card" would not be as simple as casually selecting any world one wants to enter into. Essentially, the chosen world must be of the same energy level as the world the high popularity character card originated from.
This brings to question of what energy level did "The 4WD God" actually have?
On the surface, it looked like a slice-of-life world, but if you take a closer look, you will spot the abnormalities. Whether it's the magical physical strength of the mini 4WD car racers, or the "deadly moves" of the cars themselves, such things do not occur in reality.
Therefore, generally speaking, such worlds that appear to be perfectly normal as a whole, while actually possessing a mysterious side, should be on equal standing as those "blood sports" driven worlds.
