[Grojlach]

Out of those two? Sword of Chaos is the one the djinni gives you in Irenicus' dungeon, right? Flail of Ages by far, especially if you've got all three of the heads (if you have Throne of Bhaal, two additional heads could be added as well). In my opinion the best flail in the game, and very convenient when you're fighting all kinds of trolls, you won't have to use spells (melf's acid arrows etc) or use fire/acid arrows in order to kill them then, the flail of ages will absolutely suffice then. I think one of the few items I normally equip my clerics with for the rest of the game.