KK calldown with A on board?

[albster440]

.25/.50 full 6max limit table
Writing post from my PDA so a appologive if the format isn't very pretty.

Villain is 44/15/10.5/fifty hands, seems to be getting to much respect considering how agro he is, havn't seen him show down a hand yet

Utg limps, hero raises KK, two folds blinds call.

JdAd8c - checked to me, hero bets villain in sb raises and only I call.

4s - villain bets, I call
Ts - villain bets hero?

How's my line? What if my opponent was unknown or at least not insanely agro? Is a free showdown just a spew on this turn?

This hand comes from my first day of short handed multitabling, so any sort of conceptual analysis appreciated.