Primary Law Of Darkness
As William descended the cave seemingly unimpeded, the red Rat Snake became a bit nervous. Its purpose was to guard the Superior Darkness Vein at any cost, but it could sense that the human was a true monster.
As a mutated Beast that had lived underground for a very long time, the Mutated Rat Snake had developed a keen sense of smell and hearing, and its ability to detect one's strength had been honed to an almost impossible level.
That said, when the Beast looked at William, it saw an overwhelming amount of Mana stored within the man's body, while his physical body seemed to be tougher than any material found on Efretta.
The Mutated Rat Snake found itself retreating before William even entered the main cavern opening, reducing its massive frame of five hundred meters to one meter long and sliding into a secret passage it had a subordinate create almost four-thousand years prior.