Living in the caves beneath Peng Lai Island - one of the Seven Capital Cities of Heaven – Xiang Yao is a giant snake-dragon lying in wait for the next person willing to challenge it to win the mantle of Cobra. Few who have faced the dragon had claimed victory, but the last individual in that line is Fat Cobra. It took him three attempts and two grueling defeats to finally best the creature, but Xiang Yao was decisively beaten.
It is entirely possible Xiang Yao has some relation to Shou-Lao the Undying of K'un-Lun or the Ch'i-Lin of The Eighth City, but that has yet to be revealed.