Agnes Birtalan proposed that he began his career as a fertility god, then became a spirit particularly for shamans, and ended up as a protector.
[2] As a fertility god, he granted cattle and children to people, and was a shaman for Genghis Khan with whose wife or daughter he eloped.
He can only be killed by suffocation (fire and metal cannot hurt him) and in return for not being threatened by the Khan with such a death he becomes a protector of him and his people.
[4] In 1998, Birtalan recorded a number of incantations from Xǖxenĵĭ, the descendant of a shamaness—two longer ones (a prayer and an invocation) and three shorter ones dedicated to Dayan Deerh.
[2] Dayan Deerh is often depicted as equestrian, wearing at least some typically Mongolian attributes (Birtalan mentions boots).