Wow, tough spot man. I'm no HU expert, but...

Has he over bet pot on river before? If not, it screams nutty to me. With the run out and board texture I don't think he's ever bluffing especially as his river aggression seems low with the example you gave before (but just one trial). If you use a HUD what is his river aggro%?

Given read, it's a fold. I guess he can easily have air though if he's competent and thinks about your range but random Ks are in his range too, yeah it's a fold. In saying this!... I'm assuming you posted on here because you lost the hand? If the villian is decent its clear you don't have a K and your hand is pretty face up, so it's actually a really good spot for him to do this because it is hard for you to call. He's not betting this amount to get value from his Q. I'm sticking to a fold on this nasty river because I don't think he bluffs this overbet enough to make it a profitable call.

Out of interest do you check the flop if you have AK/QK? And anypair (that hasn't made a boat)?

It makes sense for him to have 33, what did he show?

Kinda sick spot, i dont really get why he stars bluffing on the 3 blank turn..
But that means he would have checked back Kx hmm hard to say, 33 makes sense indeed.
It really depends on your reads i guess.

FYI, you're more likely to get responses if you convert the hand properly.

why not cbet ? especially if you consider AQ is the top of your range , meaning you dont have ak/AA in your checking range .... as played i'd fold but you have a capped range that is exploitable dont you ?

Im not sure, i used to cbet this 100% but lately i have started to adjust some of my ranges.

Maybe AQo is too good to c-bet here?

People seem to start floating alot more and play a more showdown heavy game, if i check AQ here i often get to showdown vs random Ax i think. Also i do check Kx here sometimes yes. especially if someone gives me the reason to do that (blindly stabbing all checkbacks etc)