Cultist trouble

Alright, I'm certain at least everyone here asks for help with cultists, but there's this one in particular I'm having difficulty with, the one in Delos, Delian League. Now I'm aware it says to help people nearby, and I know that means to complete side quests. But that's the problem, there's no side quests icons, and my quest log doesn't have any from Delos, I've already killed Kleon, so does that make him unavailable? Aspasia is also available as of now, and it will pain my brain to have to look at a 99% completed Cultist menu. S.O.S.