Ravenchast

Su Bian is someone from Earth. He went to transmigrate into the three realms era as a green snake.
A system came with him calling itself: Children Blessing System
Each time he marries or has kids, the cultivation realm improves!
Finding himself possessing a snake body, he snaked his way into the three realms!

"I want the heavens, which can not cover my sights; This land which will not block my steps; wanting the eternal way to become mine. I want to be invincible forever!"

Su Bian pointed his fingers at the skies, shouting these words at the heavens. with his snake form, he lunged and leaped with a big shout,

"I Shall Become The Heavenly Way!"

Three Realms: Children Blessing System

Some people even went as far as to speculate that the Bull Demon King, Mo Wang is the sect master of the Jie Taoism Sect, or one of the saints of Taoist Ancestor Hongjun, a Saint and even went so far as to disguise himself to a mount of a saint, which is why he is so powerful.

Such speculation is not unfounded but has a basis.

Sun Wukong is a chess piece to Buddhism, Nuwa, and The Heavens have devoted their efforts to foresee their plan, and he can only compete with the realm of the Perfect Golden Immortal.

The Bull Demon King is superior to Sun Wukong in terms of realm and combat power, and he must be somehow related to a saint.

The Bull Demon King's true form is a cow, so it's easy to guess.

The mount of the Grand Master of Heaven, one of the saints of Taoism, is a green ox. Laozi, the disguise of a pure one, once rode a green ox through the valleys and turned demons into Buddhists.

Speculations of Bull Demon King