I do think that the source is more likely Abel than Cain. It would be neat to see something from that angle, but I don't know.

I really don'T know about Cain. I think they should have shown him get killed if they wanted us to believe he was dead. But maybe they want some suspense...? They want us to be wondering if he is actually alive? We will see!

I do not think Cas overheard it. I don't think they'd go that route without a hint.

The ep was epic :D