There are several different interpretations of what happened to Childe in Genshin Impact, and the answer may depend on which source you consult. Here are some possibilities:

• According to a video on YouTube, it is unclear what happened to Childe, but there are theories that he may have been corrupted by the abyss or that he is in hiding.

• The Genshin Impact Wiki states that Childe fell into a bottomless crack in the earths surface while being pursued by bears and wolf packs. While in the abyss, he witnessed the endless possibilities of combat and was trained by a girl named Skirk.

• A post on Reddit suggests that Childe is corrupted by the abyss, and that the machine on trial is not judging him as a human.

• Another article on Genshin Lore describes Childe falling into the abyss and encountering a "beast that spoke in riddles." He also trained with Skirk and learned to fight.

• A post on FandomWire suggests that Childe may be in danger of succumbing to death, despite escaping the Fortress of Meropide.

• Finally, a story on HoYoLAB describes Childe getting lost in the winter forest of Shenzhnaya at the age of 14, with only a sword and some bread in his bag. After being rescued, he became determined to become stronger and joined the Fatui.

It is unclear which of these accounts is the most accurate, as they come from a variety of sources and may not be consistent with each other.