Inside the entire Lava Pool, there were countless Lava Giant Beasts. The royal family was probably able to control these Magma Demon Beasts. The more people entered at the same time, the more Lava Giant Beasts would appear.
If a single person entered the Lava Pool, there would be a limited number of Lava Giant Beasts that would appear, but exactly how many there would be, Yang Chen didn't know. The royal family probably wouldn't go too far, there must be a limit to the number of Lava Giant Beasts they would control. Otherwise, with the dissatisfaction of the various factions, no one would fare well in the end.