Li Gun was from Peixian. He wore a steel helmet, a suit of armour and carried a shield with a beast's head engraved on it. He was armed with a long sword and 24 javelins. Li Gun excelled in martial arts and could hit a target accurately with his javelins within a hundred steps. He did not hesistate in killing his enemies and was nicknamed 'Flying great sage' (飞天大圣).
Li Gun was a good friend of Pan Rui and served as Pan's surbordinate on Mangdang Mountain along with Xiang Chong.