Baldur's Gate II: Enhanced Edition - Part 9 De'Arnise Keep Part 2

The main item to pick up in the keep is the Flail of Ages. A contender for the best weapon in the game. It can do fire, cold and acid damage and slows down an opponent when they are hit by it. Extremely useful so you don’t want to finish the keep before you assemble it.
The forge to assemble the Flail is in the south west of the ground floor behind a hidden door. The first head of the flail can be found behind a hidden door in the forge room. The final to heads can be found on the 1st floor. The charmed captain of the Guard has one (just use dispel magic on him to break the enchantment. You can fight him but he is tough) and the last piece can be found in the room full of Golems.
TorGal the leader of the Trolls can be lured away from his group and fought 6 v 1. That along with your new Flail of Ages will mean you can defeat him without too much trouble. Trying to defeat him along with the two other trolls backing him up is unwise.