The Drunken Lizard Pub

I'm just starting the game and have finished a couple of the early quests. I accepted the quest from Xed to kill Harpen and then the subsequent quest to kill Xed from Harpen. However, when I get back to Xed he won't engage me. Is there some way to force a fight?

Just like with attacking inanimate objects, you can hold down the shift key to force an attack on a friendly NPC, or you can right-click to cast an offensive spell on him if you are a mage.

Or go and loot his chest by the fire and that should make him hostile. This will cause you to fail the true thief challenge.

Got it and thanks for the help. As a nub to RPGs I'm sure I'll be back for more advice but I'm definitely enjoying the game.