Zhang is a Pixiu. It is a Chinese mythical hybrid creature. Pixiu are considered powerful protectors of feng shui practitioners, and resemble strong, winged lions. A Pixiu is an auspicious creature for wealth, and is said to have a voracious appetite exclusively for gold, silver, and jewels. Therefore, traditionally to the Chinese, Pixiu have always been regarded as auspicious creatures that possessed mystical powers capable of drawing cai qi (財氣 wealth) from all directions,and according to the Chinese zodiac, it is especially helpful for those who are going through a bad year.

Zhang, however, was first a protector of Caishen. Caishen is often depicted riding a black tiger and holding a golden rod. He may also be depicted with an iron tool capable of turning stone and iron into gold. When Zhang fell in love with humanity, he begged for Casihen to let him go so he can start protecting humans suffering from band Feng Shui instead.