The Tibetan traditions have avoided the attribution to him of theistic qualities by stressing his nature as śūnyatā, and by seeing his purpose as essentially that of a device within the confines of tantric practice. His bīja mantra is OM.AH.HUM., which represents the body, speech, and mind of all buddhas.
"Ādi Buddha." The Concise Oxford Dictionary of World Religions. . Encyclopedia.com. (August 20, 2018). http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/adi-buddha
"Ādi Buddha." The Concise Oxford Dictionary of World Religions. . Retrieved August 20, 2018 from Encyclopedia.com: http://www.encyclopedia.com/religion/dictionaries-thesauruses-pictures-and-press-releases/adi-buddha