I was randomly killing adds in a escalation protocol and got the Darci catalyst to drop. I did not have a Darci on or even in my inventory so I think they drop randomly. It’s the what you do after that that matters. For my crimson catalyst I needed precision kills. I could be wrong but just wanted to share. Hope it helps! Best of luck Edit: looking forward to see an update here as I really want to try the prospector lol post back here the results