For Yoruba traditions, there is no centralized authority; because of this, there are many different ways that Yoruba people and their descendants or orisa-based faiths can understand the idea of Olorun. Historically, the Yoruba worship Olorun through the agency of the orisa; thus there is no image, shrine or sacrifice made directly towards Olorun. There is some controversy about whether Olodumare is directly worshiped, due to their aloofness from humanity. However, there are those who also worship Olodumare directly. Olodumare is the origin of virtue and mortality, and bestows the knowledge of things upon all persons when they are born. They are omnipotent, transcendent, unique, all knowing, good, and evil. The Yoruba call on Olodumare when other deities (orishas) seem unwilling or incapable to help. These orisa or orishas are supernatural beings, both good (egungun) and bad (ajogun), who represent human activity and natural forces. Yoruba believe Olodumare created all other forces of the universe to help continue the evolution of the universe.