天姿穎悟 Ten Thousand Heavenly Troops Failed
逐句解 Line by line
My own nature I cultivated myself, and that was no small thing; heaven-given gifts, quick understanding, and the great elixir at the head of it.
大丹 is the great elixir of the inner alchemists — not a pill to be swallowed but a process worked inside the body, refining breath and essence into something that does not die. Wukong is claiming the full course, and claiming he did it by himself.
Titled Great Sage by office, I lived in a cloud mansion; leaning on my strength I turned savage and fought the Dipper and the Ox.
斗牛 is a pair of lunar mansions, the Dipper and the Ox, and 斗 is dǒu for the constellation rather than the fighting reading it looks like. He is admitting, cheerfully, that he was given an office and abused it — and the phrase for turning savage is the same one the narrator used of Bajie at the cave door.
A hundred thousand heavenly soldiers could not come near me; the whole sky of lunar mansions was easy to gather in.
宿 is xiù here, a lunar lodge — a division of the sky, not the sleeping reading. 為 is wéi, in the sense of a thing being easy to do, rather than the for-the-sake-of reading it carries elsewhere in this chapter.
The middle of the autobiography is a war record, and Wukong tells it without a flicker of embarrassment. He was given a title, he misused it, he fought the armies of heaven and they could not touch him. Every word is true.
The elixir claim matters more than it looks. Inner alchemy was normally taught by a master to a disciple over decades, and Wukong is saying he refined his own nature himself. In a chapter whose title calls him the Metal Lord — one of the alchemical names for what he stands for — that is not a throwaway boast.