I see, but am not sure if someone else than our fellows from Radiant can already answer in this detail.
Based on the Mod-Stream, I could imagine that you could adjust the “Observer”-System of the Villager-Class to react on the Ronin. As each creature in the game should run as a separate thread, so they will have a separate list of variables once generated. You could add another variable into the Villager-Class which tracks his standing towards the Ronin (just like there will be a variable tracking hunger, etc.). Once the villager meets the Ronin, the “Observer” of the specific Villager-AI will has to fire a message to the “Intention”-System. Either the “Observer”- or “Intention”-System will have to check for the variable which tracks the standing towards your Ronin. Based on the standing you can fire the right activity-request to the “Action”-System and also adjust the variable (e.g. reduce threat-level each time your villager meets the Ronin).
I guess you can also expect that there is the possibility that one AI is sending messages (activities) to another AI. In this case you could implement the logic in your Ronin-Class and send activities to the villagers crossing his path. But here I do not think that it will be efficient to track the standing of each single villager in the Ronin-Class (might be quite some at the end of the day). However, if you want to have just one Standing (Townspeople vs. Ronin), that might be the better place to put the logic in.