The Moro clan is a group of wolves living in the forest of the Forest Spirit. Not much is known about the clan as a whole aside from their duty in protecting the forest and per proxy also guard the Forest Spirit. Only four members of the clan are ever seen, and it is not mentioned whether or not there are more. The four members are Moro, Moro's two (unnamed) pups, and San (Moro's adoptive child).
The clan may once have had a partnership with the Boar clan, and may have fought alongside them once before the events in the film.