"Throughout the legends, there is mention of a Spirit Guide who appears in times of need. Imbued with divine power, (s)he aids the weak and helps maintain the Tao. It is disputed amongst scholars whether the Spirit Guide truly exists and, if (s)he does, whether (s)he is a god or merely a servant of the gods. Some even suggest that the Spirit Guide appears in times of need because (s)he is actually the source of the threat and must appear in person to see his/her plans through to completion."
Eldridge was a Spirit Guide that appeared during the events of The Shattering.
To date, there has been no other appearance.