Xuan Tian

This is an image of the god Xuantian, (Mysterious heaven).  He is a slightly more martial form of the same god also called Ziwei or Zhenwu (Perfected Warrior).  Xiantian is the god who also goes by the name Xuande (Mysterious Nature), the god who met with Zhang Sanfeng the night before he invented Taijiquan on Wudang Mountian.

The names represent earlier and later parts of our era, times in which the god's job has changed.  Since all the names are still used, he is still available to do all the jobs.