Kūkai held, along with the Chinese and the Tendai schools, that all phenomena could be expressed as 'letters' in a 'World-Text'. Mantra, mudra, and mandala are special because they constitute the 'language' through which the Dharmakāya (i.e. Reality itself) communicates. Although portrayed through the use of anthropomorphic metaphors, Shingon does not see the Dharmakaya Buddha as a separate entity standing apart from the universe. Instead, the deity "is" the universe properly understood: the union of emptiness, Buddha nature, and all phenomena. Kūkai wrote that "the great Self embraces in itself each and all existences".