Not being an asshat leads to romance option, no?
In spite of what Larian claimed, there doesn't seem to be a non-romance relationship path. You are either disliked or companions try to engage with romance everyonce in a while. Some of them at least. In my playthrough Karlach made no such move - I assume she is one of the few characters who won't try to romance you if you initiated romance with someone else? The downside is, that she doesn't seem to have much content beside "upgrade the engine" thing (deep into act2 now - I assume she will get a more significant location in act3). I am not sure if she ever told me about the engine properly.
Eh too bad. Just another RPG, where companion interactions end up being mostly reduced to a bad dating sim.
