I totally and purposefully killed a character of a player that wasn't at my session last night. Granted, I feel the monsters were doing what they should have been doing, but I went into the session with the mindset of being ok with killing one of them.
The fight itself was tough and positioning was a real ordeal, and many other things. As a result, the half-orc was dead, in the corner, molested by poltergeists and yuan-ti boneshard skeletons. He got up, two rounds later. He was feeling much better.
Yes, the death resulted in furthering a part of the story. Was I really gunning for him? Maybe more than I should have been. Though, for the most part, I think the monsters stayed acting how they should act. However, this is the second occasion in which I have injured or killed a player and it results in a plot point. Perhaps this is the wrong way to go about things. I hope that the story and options that result from it will be fun, and offer interesting choices to the players.
I might be making a mistake, though. Regardless, something like this I probably won't do again, at least, certainly not soon.