I did a minor run through of the game and there were two items (that I am aware of) that I didn't come across, the liquid mercury, and runestone needed for the Runehammer, if anyone knows where they are help would be much appreciated, and also what is a better combination, Holy Avenger and Eye of Tethyr or Purifier and Eye of Tethyr?

Hmm...

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I found both the liquid mercury and runehammer rune. I am certain they were both in the area with the drow bhaalspawn, and I'm fairly confident one or both were in the lich's chamber.

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Actually, now that I think about it, the rune for runehammer is definitely in the woodsman's house in the drow area.