Here it says:
"Karl Chiaku After Razril's sunset scene, spend the night at the inn in Razril and then speak with Karl in the back streets."
I try to gather all Deborah's quotes now, so I skipped many recruitable characters. Now I have 60, and Karl still refuses to join and tells me to come later. So I assume you should have at least a certain number of recruits in order to get Karl.
Anybody else came across this?