To get the Conquest Ending you need to view 3 "demon sword rumor" events in 3 of the towns. From what I've heard these locations are:
Slayer in Lastation, Magicom Mama in Lowee, and Big Adventurer in Leanbox)
I've heard mixed reports of whether they show up before or during Chapter 5 (unfortunately my current save is chapter 5 but I have a backup in chapter 4), but I haven't been able to reliably find these characters before or after chapter 5. I've seen Magicom Mama before (I'd swear it was during chapter 5 actually) but now that I want to get this ending I can't find any of them in either chapter 4 or 5.
Is there some trick to getting these NPCs to appear on the Chirper or is it just random chance? If it's random, do I just exit/enter town until I see the NPCs or what?