The monks said: "He told us of that Great Sage:

那 is nà, pointing at a Great Sage they do not know is listening. The line introduces the description the Star of Venus gave them in dream.

A knobbed brow, golden eyes flashing bright; a round head, a furred face without jowls.

磕額 is a knobbed, jutting forehead; 無腮, no cheeks to speak of — the flat-sided face of a monkey rather than the full jaw of a man. The portrait is unflattering from the first line, which is how you know it is accurate.

Jutting teeth, a pointed muzzle, a nature wild and wayward.

咨牙, teeth bared and showing. 乖 is not the modern "well-behaved" here but its older sense, contrary and willful — the same character has traveled a long way.

In looks a match for the Thunder God, grotesque.

雷公 — the Thunder God of the translation, "Thunder Duke" if you take 公 literally — is drawn with a beaked face and a monkey's build, which is why the novel reaches for him whenever it wants to say what Wukong looks like. Anyone in a Ming audience had seen the picture.

Wont to wield the golden-hooped iron rod; once he battered the gates of Heaven open.

The one deed everybody knows. 天闕 is the gate-tower of Heaven, and battering it open is the 大鬧天宮, the havoc in Heaven that occupies the novel's opening chapters. 將 is jiāng, taking the gate and doing something to it.

Now, turned to the right, he comes to guard the monks;

皈正, to turn back to the right — the formal word for taking refuge, for a convert coming over. One line for the rebellion, one line for the conversion.

his whole care to save the world of men from calamity."

And the new job, stated as a vocation: 專救, to save and do nothing else. 間 is jiān.