Ren is definitely going to be curious about what's causing the fires - since he's more of a connections kind of person, he's probably going to ask around and try to get information off the locals about locations and circumstances of the fires to see if there's any pattern to them (and if there isn't one...well, all info is good info so someone can probably do something with it anyway, he's not picky).

If he does hear of anything that might be a lead, or if anyone mentions having seen potential causes of the fire, he'd probably get more specific in his investigating then.