It is obviously Proxxy/Cain. Most likely Cain, though, as Proxxy is more likely to throw a legion of searchbots at us, then boost them with her own powers. As has been shown, Oric is not our enemy (yet), Betweenford has engaged no hostile actions against us (again, yet), and none of the other siblings have been discovered.
Also, I agree with hard-hat-tactics.
He said a clever researcher, which means it's been listed or at least hinted at somewhere. Cain might have during his breakout thing, but Proxxy's never hit anything and I think I'd remember her having a 1d12 lightning axe or something. In fact, wasn't her only weapon a 1d4+2 cattle prod or something?
Hard hat is a good point, but I'm not sure that helps us enough. We'd need to enter tactical combat to use it (or possibly just have goom-bess guard instead of attacking), then have her tank all the damage somehow while we kill them. Recall that these searchbots are acting suspiciously intelligent, however, so they probably wouldn't stand there and wail on Goom-Bess while we shoot them to death.
EDIT: Now, if we could figure out what they're after and hand the character holding it the hardhat
maybe... but that'd require presenting ourselves as delectable morsels to figure out which the searchbots most wanted to devour.
EDITEDIT: Oh. OHHHHHHHHHHH. Wait, no. These searchbots aren't working for Proxxy. I thought they were after the scout eye, which made sense, that's stolen property... but the only way that could be true is if they were some sort of meta-justice force so bent on their mission they were willing to plow right through someone's goons in order to get their stuff back.
...or if the scout eye didn't originally belong to Proxxy in the first place. Hrm.
Still, it's worth noting that we have nothing else they might want. The key maybe, the eye as I've mentioned... but otherwise what? The persuasion ring? Cherish? The skill tree? I think our assumption that they're retrieving an item from us is missing some pieces or not correct.
And, also, considering that he said that he didn't want to give us clues, it means that we are pretty much screwed, and that's why he helps us.
I think this was less "oh shit they're going to die and I can't allow that because X," and more "well no update today, say know what nobody seems to quite have a grasp on? Damage mechanics, maybe I'll talk about those."
I don't doubt the current situation helped inspire that, but I don't think he's secretly yelling at us to use the hardhat or perish.