Also, if you ever played Dark Forces II from 1997, the main baddie is a former Inquisitor named Jerec. That was the first time I had ever heard of them. They didn't do the whole "3rd Sister, 5th Brother, etc" thing back then. I always had the impression they were more of an intelligence organization of Force sensitives sniffing out Jedi for Vader rather than taking them out themselves though but maybe I'm wrong. Of course, that iteration is not canon now, if it ever was. I was surprised to see the concept pop up again in Rebels.