Ayyaana is one of the central theological concepts of the Oromo and is best understood as the manifestation-spirit of Waaqa. In Oromo philosophy everything that exists emanates from Waaqa in the form of ayyaana, the immaterial principle that gives each individual entity its particular essence; through the ayyaana the creator, in the formulation of the scholar Gemetchu Megerssa, propels himself into becoming his own opposite and comes to dwell within what he has created. Conceived as intangible spirits living near human dwellings, often by holy groves, the ayyaana are attached to clans and persons and act as intermediaries between Waaqa and humankind, shaping a person's fortunes in proportion to their observance of the moral order safuu. Because the ayyaana is an emanation of and wholly dependent upon Waaqa, it is treated here as a distinct but subordinate divine principle rather than an independent god.