The first time, Dean only heard about the "other Crowleys", and the subject didn't interested him particularly, nor did he Path much attention to it. Later, even after having met them, he never did remember exctly how they had ended up talking about it. It probably was something to do with family or with the bond between Meg and Azazel, seeing what they ended up discussing. However it had happened, Dean had ended up asking the demon if he had any family. The funny thing was that he did, and would rather have preferred not talking about it, which meant that of course Dean insisted.
-So how many "relatives" do you have?- -Two, my teacher, the one who could be considered my "father" and my younger "sister", who isn't really a demon, but his daughter- -So...wait, wait, wait...I have a few questions, is your "father" the one who tortured you to turn you into a demon? Do you have anything in common? Is your little sister a cambion then?- -No, my teacher isn't the one who tortured me, he wouldn't be interested in that, he's the one who taught me how to be a demon after I had been broken, we don't have any physical similarities, but we all use the last name Crowley, and my "sister" Lizzie isn't a cambion but a Nephilim, as my teacher is one of the original fallen angels, he's quite powerful as such, and while the other fallen and many of the high ranking demons don't like him because of his attitude, most other demons respect him both because of the role had and because of all the innovations he had brought both in hell and on earth, before his intervention crossroad contracts were ridiculously easy to get out of because of all of the loopholes they had- -So we might have to deal with him? And what was that about his role?- -I doubt it, he generally tend to stay out of hell's big projects, he'd probably try and ignore that there was an apocalypse going on, as for his role, he's the Serpent of Eden-. Some more talking ended up with Crowley revealing that there was a ritual to summon Lizzie Crowley, but he refused to tell what it was. He would later be able to get Sam to find it, and understood why Crowley didn't want to talk about it: while most summoning rituals needed things such as blood, animal parts and other creepy things, in that aspect Lizzie's ritual was easy, it had to be drawn with coloured chalk, and required a bowl of salat dressing, a plate of fresh celery stalks and a sliced apple, all things a lot of people actually had in the fridge, and not very impressive.