Genghis Kahn

Genghis Khan was the founder, Khan (ruler) and Khagan (emperor) of the Mongol Empire, the largest contiguous empire in history. He came to power by uniting many of the nomadic tribes of northeast Asia. After founding the Mongol Empire and being proclaimed "Genghis Khan", he started the Mongol invasions and raids of the Kara-Khitan Khanate, Caucasus, Khwarezmid Empire, Western Xia and Jin dynasties. During his life, the Mongol Empire eventually occupied a substantial portion of Central Asia and China.
In 1211, after the conquest of Western Xia, Genghis Khan planned again to conquer the Jin Dynasty. The commander of the Jin Dynasty army made a tactical mistake in not attacking the Mongols at the first opportunity. Instead, the Jin commander sent a messenger, Ming-Tan, to the Mongol side, who promptly defected and told the Mongols that the Jin army was waiting on the other side of the pass. At this engagement fought at Badger Pass the Mongols massacred thousands of Jin troops.