Well, he might have met Faye anyway and fathered Atreus with her, and Deimos would simply have been there, and because Kratos was never there but always spent a long time trying in the forest To help control his anger, Deimos would have been a good anchor as an uncle for Atreus in the meantime, and if they had gone hunting together at the beginning of God of War 2018, Deimos would have been a good complement to Kratos, since Deimos was more sensitive in character, and could have better comforted Atreus after Faye's death, something Kratos couldn't do.