Over the past weekend I went to see the movie Fury with some friends. It's a good movie, and I don't want to ruin anything but the summary for the movie on Rotten Tomatoes says that it's a group of soldiers, in a tank, behind enemy lines, and they're out numbered and out gunned. I feel that means it is safe to say things are dire. The kind of dire where, were it to be a Table Top Role Playing Game I would expect PC deaths - if not a TPK - to be the result at the end of the day. And that is something worth talking about.
Different Kinds Of Player Character Death
If you think about it you probably already realize this, but there are different kinds of PC death.
Some PCs die because the dice just turn against them. A combat that was winnable has some bad dice rolls and next thing you know a PC is on the floor and failing their stabilization check. These are the kind of deaths that many GM and players don't like - and other players and GMs absolutely love - because they just seem so random and can make it hard for long term plots that involve specific PCs because, well, they could be dead at any moment.
Some PCs die because the GM makes an error and flat out makes an engagement too hard for the PCs with little to no way out of it. This is a failure in planning and mechanics more so than anything else. These also suck for the GM because, well, it always blows when you realize that something meant to be challenging is actually overwhelming and you tricked/forced people into it. Thankfully, these are - in most groups I've seen - incredibly rare.
Some PCs die because the GM is actively trying to kill PCs. I disagree with these as a rule, but some GMs and Players seem to like it and that's cool. The idea here is the GM is actively - for better or ill - trying to remove a PC from the game. Whether it works or not often comes down to the dice, but in my opinion it is the extreme of adversarial GMing and not something I recommend you do without chatting with your players.
Then, finally, some PCs die because the players made a choice. These are weird because they can feel like the second one to the GM. It can be hard to tell why the players made a choice, and if they felt coerced/forced than it can make the GM feel bad. It is this last one I want to talk about.
Who Is To Blame
You're GMing a fantasy game. The PCs are holed up in a castle that is evacuating because a dark army is on the march. Important NPCs are evacuating, but some plan to stay to buy time for the rest of the world. The PCs have the choice of evacuating and protecting the refugees, or staying to fight. They choose to fight. They all die in the sacking of the castle. Your game is effectively over.
Who is at fault?
Is the GM at fault for crushing the PCs in an unwinnable fight? Are the players at fault for choosing to stay when they could have left?
Objectively, and from the outside, it can be easy to see. In the heat of the moment though it can be much much harder.
Respect The Player's Choice
Obviously with the topic of the day and the post, I say this is the player's fault. Perhaps fault is the wrong word though. Fault implies it is the wrong answer, and the only wrong answer in an RPG is one that destroys the fun of the game.
The players have made a choice in this example. They have chosen to stay and be part of the stalling action against the tide of darkness coming for them. They have chosen not to flee. In effect, they have chosen death. As the GM, that is something worth respecting, because if nothing else it means at that moment the players decided that the story they wanted for those characters involved being a part of that stand. Your job then as a GM is to make that stand suitably epic.
But how do you know it is a choice? For it to be a choice there has to be multiple valid options. As the GM in this situation your job would be to make sure that the PCs know that staying is likely to end in death, leaving with the evacuees is an option, and that neither is right or wrong, they just have their own consequences.
From there on out it is the players' choice.
In The Field
In the field it can be harder to see as clear. But look back over your last session or adventures where someone died. Why did they die? Was it a bad roll? Was it because the adventure demanded a death? Or was it because it was a fate that they ultimately chose for themselves?
Talk about it with your players too. I am continuously surprised at how many players will, in the right circumstances, choose a path that means death for their character because it is the right - and/or awesome - thing to do at the moment.