Chin has two nicknames: Chin, the Great, the nickname given to him by the village of Chin (which is named after him), and Chin, the Conqueror, the name given to him by Avatar Kyoshi.  To this day the town of Chin believes Chin was a great man and pretty much a saint.

About 370 years ago, Chin was the most powerful man in the world.  He and his armies took over almost the entire Earth Kingdom continent in a matter of years.  But one person stood in his way of conquering the entire continent: Avatar Kyoshi.  His troops arrived at Avatar Kyoshi’s village.  But Kyoshi told Chin she would not sit around and let him just take over her people.  So she triggered her Avatar State on cue (which Aang was unable to do, mind you) and used the elements to separate her village and form a new island where her people could live in peace.  It was named Kyoshi Island.

There is a huge discrepancy about what happened that day.  Avatar Kyoshi’s account was that he stomped on a small piece of Earth that was connected to nothing more than the edge of a cliff, and he plummeted to the bottom, promptly dying upon impact.