Bayarmaa is a werewolf.
Oz met on his quest to tame his inner wolf. After the incident in Sunndale University with Tara Maclay and the Initiative (recap in issue #27 of Season Eight) he returned to the Buddhist temples to resume his training in controlling the wolf only to find nothing worked. It was Bayarmaa who helped him find a way. She taught him to "Be a river..." to let the energy of the wolf flow through him without taking over his mind. Eventually the two became romantically involved. It has not been confirmed whether they are married but they share a son, Kelden and when Oz introduces her to Buffy and the rest he calls her the rest of who he is. The gang does not immediately take to her and are always voicing concern to Willow who was Oz's original love. She has not tried to hide her displeasure at Buffy and her gang for bringing trouble to what was her peaceful home in Tibet.
When Bayarmaa tranforms she turns into a large brown colored wolf.