Ineffable Fate

Crowley and Aziraphale are... well what exactly are they? Are they partners, friends or more than that?
The only thing that is certain is that they belong to each other, they somehow complete each other. An angel and a demon being platonic (or romantic?) soulmates is pretty much unheard-of, but it is not one of a kind.
A trip through the multiverse will show us just how much Crowleys and Aziraphales fates are linked with each other, no matter the circumstances around them