The one in the middle looked like this:

生得 — born looking like — is the standard tag that opens a portrait poem, and 得 takes its light de here, the grammar that hooks a description onto a verb. Three earlier chapters put it in exactly this spot and read it de every time.

Chisel fangs and saw teeth, a round skull and a square face.

Four tools in four characters: a chisel, a saw, a circle, a square. 圓 and 方 are also the oldest Chinese shorthand for Heaven and Earth, so a face built out of both is quietly enormous.

A voice that roared like thunder, eyes flashing like lightning.

Thunder and lightning, in that order, which is the order the couplet needs and not the order weather arrives in. Sound then light: the reader hears the thing before seeing it, exactly as Wukong would from behind a wall.

Nostrils tipped up to heaven, red brows streaming flame.

朝 is cháo, facing toward — the same character that gives the word for an imperial audience, which is roughly what is about to happen. An upturned muzzle is a lion's, and it is also the face of someone who has never had to look up at anybody.

Wherever he walked, a hundred beasts lost their nerve; if he sat down, the whole crowd of demons shook in their gall.

Another pair printed as one sentence and split by a semicolon, folded back here because they answer each other exactly: three characters of condition, four of consequence, on both sides. 膽戰 — the gall trembling — is still live Chinese for terror, and it survives in 膽戰心驚. Chinese medicine housed courage in the gall bladder, so this is not a metaphor so much as an old diagnosis.

This one was the king among beasts, the Green-Haired Lion Fiend.

獸中王 — king among beasts — with 中 as plain zhōng, in the middle of. He is also, at this moment, literally the one in the middle seat, which is how Chinese seating has always announced rank.