The Underworld Hell possessed the "Eternal Existence" effect, and could also draw enemies inside it. It inherently possessed sealing and suppression-killing abilities.
The Undead Bone Sacred Mountain did not even possess sealing abilities yet. Its sealing power only manifested when it unleashed that force and brought the mountain down like a great seal.
The Netherworld Ghost Market did possess sealing abilities, but trapping external enemies inside would continuously consume Red Frost and the Ghost Market's power.
The Underworld Hell's sealing and suppressive power, and even its concept of eternal existence, all existed naturally.
Strengthening these powers or activating the effects of the Underworld Hell's nine levels of punishment required energy, but at the same time, the Underworld Hell could devour evil karma and form sin power several grades higher than the energy of heaven and earth.
To a certain extent, imprisoning criminals in the Ninefold Underworld Hell could allow it to function as a self-sufficient perpetual-motion machine.
Likewise, imprisoning criminals also benefited Rakshasa herself. The Underworld Hell needed to constantly absorb sin.
"But Tian Yuan City can't find that many guilty people."
"No, I was thinking too narrowly. Why limit ourselves to humans? Legendary Monsters can serve as batteries too. And we won't need to hold back when squeezing them dry."
How perfect.
Since he had decided to do it, Mu Yuan continued flipping through the Sky Patrol Mirror in his hand, thinking about finding a suitable vessel for the Ninefold Underworld Hell.
Finding a vessel, merging the Underworld Hell into it, and using the power of reality to continuously strengthen it... this was no easy task either.
Mu Yuan immediately pulled Deathbone, Isroya, Red Frost, and Rakshasa into a small group to discuss the matter.
Deathbone: "A highly feasible idea. As expected of our Lord!"
Isroya: "...Tian Yuan City