This prince, three days old, went down into the sea to wash himself and got into trouble. He trampled the Crystal Palace flat and caught a scaly dragon, meaning to draw out its sinews for a sash-cord.

三朝兒 is the third day after a birth, and 朝 is zhāo, a day — not the cháo of a court, which the same character is everywhere else in this chapter. 三朝 was a real occasion: the third-day washing, when a newborn was bathed and shown to the family. Nezha goes to his in the sea and wrecks a palace. 倒 is dǎo, to fall — trampled it down — not the dào of reversed. 為 is wéi, to make into.

The Heavenly King learned of it and, fearing what would come of it later, wanted to kill him.

後患 is later trouble, the consequence that has not arrived yet, and it is still the ordinary word. A father proposing to kill a three-day-old to prevent an incident is told here in eleven characters, without comment.

Nezha flew into a rage. Taking the blade in his own hand, he cut off his flesh and gave it back to his mother, scraped his bones and gave them back to his father, and returned to them the seed and blood of his parents.

This is the scene everything else about Nezha is remembered for, and its language is bookkeeping. All three 還 are huán, to give a thing back to its owner — not the hái of still or yet. What a child receives from its parents is flesh, bone and the blood that made it, and Nezha settles the account item by item. 父精母血 is the father's seed and the mother's blood, the standard account of how a body is made. Filial duty said the body was not yours; Nezha agrees, and hands it over.