Akal purakh is in everyone. His roop is in vishnu, shiv, etc. But he himself (akal purakh) is without form. He is the one who has created every devi, devta to perform and look after various areas of his creation. Vishnu has come in many avtars over the centeries in ram, krishnan, narsing etc.
Guru gobind singh ji has given his stated in jaap sahib ki what the almighthy himself is.
This is all that i know. If wrong, pls accept my apologies. I to am also learning.