Villain is 18/15, has 5% donkbet over 2400 hands. We have played a decent amount together and got into a 3/4bet war in the past. I'm having a hard time putting him on a range here.

I don't get what he's donking with here, since his donkbet range is so small, that he just flats my raise.

Is a turn bet/fold best here?

Full Tilt Poker $0.25/$0.50 No Limit Hold'em - 8 players
The Official 2+2 Hand Converter Powered By DeucesCracked.com

CO: $52.00
BTN: $157.00
SB: $84.50
BB: $51.25
UTG: $61.35
Hero (UTG+1): $70.95
MP1: $50.00
MP2: $53.55

Pre Flop: ($0.75) Hero is UTG+1 with K K
1 fold, Hero raises to $2, 4 folds, SB calls $1.75, BB requests TIME, 1 fold

Flop: ($4.50) 3 7 8 (2 players)
SB bets $2, Hero raises to $7, SB calls $5

Turn: ($18.50) A (2 players)
SB checks, Hero checks

River: ($18.50) Q (2 players)
SB bets $15, Hero requests TIME, and then . . . ????

If I have history with someone or he thinks we have some, I'm always donking a set or 109hh here, nothing else, trying to get you to spaz. I fold river very quick in your spot.

raising flop is pretty spewy. when you get in you're never happy about what you see. raise/folding with position is just bad.

I dug through some more stats, and he hasn't 3bet an EP open from the blinds in 100 chances, and has a 10% call open from the SB.

oh as played i'd b/f turn and hope for something along the lines of T9hh.

Even though he's very aggressive I would give him credit for a big hand like a set or a rivered flush here. Both kind of hands make sense so I would fold. I mean there are not that many hands that he donk/calls the flop and bluffs the river except maybe 65 or T9 (both not with two hearts cause this might be a 3bet).

Of course there is a chance that he thinks you were afraid of the turn Ace and therefore tries to get you off a better hand but you have to be right 30% of the time.

checking turn is just telling him that you do not have an ace: he can make u fold with ATC.

b/f turn ftw!