The Siege of Dragonspear achievement "Grim Deeds To Come..." is technically unachieveable as of 6/30. There will eventually be a patch according to Beam Dog, however in the mean time the steam user Julius Borisov, who is listed as a developer for the game, has posted links to workarounds for both Grim Deeds and You Chose Poorly (which is buggy but not unachievable in game).
Since a developer of the game is officially recommending this, it can probably be considered a legitimate way to unlock the achievements for the time being. It does involve the use of a mod called weidu, though they also provide in-game console method of unlocking if you do not want to use the mod.
http://steamcommunity.com/app/228280/discussions/0/135509024...Hope that helps anyone who is still wanting to 100% this game but not wait any longer for Beam Dog to actually fix it.