There are different types of living entities according to their different karma, but the Lord claims that He is the father of all living entities, and therefore the Lord descends to reclaim all these forgotten conditioned souls back to the sanātana-dhāma, the sanātana sky, so that the sanātana living entity may again reinstall in his sanātana position in eternal association of the Lord. He comes Himself by different incarnations, He sends His confidential servitor as sons or associates or ācāryas to reclaim the conditioned souls.
And therefore sanātana-dharma does not mean any sectarian process of religion. It is the eternal function of the eternal living entities in relationship with the eternal Supreme Lord.