Based on the provided text, who were the main individuals involved in the incident in front of Sai Baba, and what were their roles?

The incident described in Chapter 24 involved several individuals serving Sai Baba. The central figures in the quarrel were Damu Anna and Mavshibai. Anna, a man past fifty with no teeth, was pressing Baba's left hand. Mavshibai, whose original name was Venubai Kaujalgi, was a devoted widow of mature age whom Baba called "Mother." Her role was to massage Baba's stomach with great vigor. Sai Baba himself was the object of their service and acted as the neutral observer who ultimately became the wise mediator, using a "powerful trick" to lovingly reconcile his quarreling devotees and restore harmony.