The Demon Kings refined the essence blood of the Evil God, each one making substantial progress in strength, and nearly all of them were about to enter seclusion to digest their gains.
The Ox Demon King also felt that he was just short of an opportunity to ascend to the Second Heaven of the Da Luo Golden Immortal. He needed a moment of epiphany, to feel the principles, before he could truly understand how the laws came into being.
Laws are determined by the Heavenly Dao, while the rules are established by the Great Dao. Though they differ by only one word, the discrepancy is as vast as a thousand miles.