Woot, managed to defeat a Troll today at the Ruined Keep nearby Owl's Head. My first try at fighting it, I used my Archery deck but only got him to half health. His health regeneration was too much for my dps. That and with the ground pound at melee range and rock throw at ranged, made quick work of me. I changed to my 2-handed blades melee deck for my next attempt and this time made greater headway, getting the Troll to about 400 health. My next attempt, I included rend in my deck to keep the Troll's hp regeneration to a minimum. I also included Coup de Grace for the finisher. During the fight, the Troll sprinted away to get some distance between us in order to throw his rock, but I chased after him and made sure he was in melee range..Sure enough, when I closed the gap, the Troll did not execute its throwing animation. I made sure to be always behind the troll or standing on his hit-box so that he couldn't throw his rock at me. Surprisingly, this made the fight much easier, as he couldn't stun me. I managed to defeat him with about 50% of my health remaining.
My equipped gear when I took him down: Founder's plate armor (ordinary plate armor) and Ornate Flamberge (ordinary 2H sword).