Here are some points about the Purusa-avataras.  To understand these different forms of God helps us to gain a better understanding of Vishnu tattva and our Vaishnava Siddhanta as presented by A.C. Bhaktivedanta Swami Prabhupada.

1. Karanadakasayi Visnu (Maha Visnu). He rests on the Causal Ocean (karana means ‘causal’).  All the universes emanate from Him when He throws His glance on the material sky. He is the Supersoul of the collective universes. The universes manifest through the pores on His skin.

2. Garbhodakasayi Visnu (Hiranyagarbha Visnu).  He is the Supersoul of the aggregate of living entities (the “Universal Supersoul”).

3.  Ksirodakasayi Visnu.  He is the Supersoul of each individual living being.