Legend has it that once when a simple love game between Lord Shiva and Goddess Parvati became serious. It built up to such intensity that Lord Shiva intended to walk out. When all efforts of Devi Parvati failed to pacify Her beloved consort, She manifested Herself into the fierce (Ugra roop) form of Maa Kali. Seeing this terrible form, it is said, Lord Shiva took flight but every direction He ran to had one more form of Divine Mother. Thus the 10 forms, the Dus Mahavidya manifested. So the Lord could not escape. The Dus Mahavidyas made Lord Shiva aware of the eternal love which existed between Him and Devi Parvati. Seeing the forms of the Dus Mahavidya, which ranged from scary and fearful(Ugra roop) to stunningly beautiful(Soumya roop), is said to have had a spiritual awakening in the Lord. Therefore, the Dus Mahavidya Devis are manifestations of the Divine Mother to bring about shifts in energies and spiritual awakening in the human race.