The rise in energy cost made sense to Cain. He was mixing in several different sources of Law energy principles.
These mutated forces surpass the rules and laws of the standard Great Dao. Exhibiting forces that can truly be considered heaven-defying.
Since this will be a continuous battle gauntlet with highly powerful Divine Decree Lords, Cain took more of a notice with his energy management.
Some Divine Decree Lord could have a skill that'll make him waste more energy than he should. And while Cain can roll over Late Stage Divine Rulers, any accident can still occur.
There was even the possibility of Cain making a grave mistake and needing to teleport himself out of the Starry Earth Realm!
Still, even knowing this risk, he wasn't going to stop this path.
Lord Fire represents the highest tier of Divine Rulers under Lord Chao and Lord Chen. Geniuses like Lord Fire will become instantly suppressed by Cain in one attack!
