As the DM, you are the final arbiter of life and death in the game. You decide when to fudge the die and say that killer blow goes wide, or to draw your thumb across your throat and say that the PC dies. You set the tone of the campaign, such that the players can either relax and know deep down in their bones that everything will be OK, no matter how rough the situation seems, or sit on the edge of their seats, terrified that this time round it's all going to end for good. So where do you stand? How forgiving, how brutal should you be as a DM?

When I first started out, I was known as the 'Murder DM'. My philosophy was as follows: if the players know that death is on the line, it will make any victory all the sweeter for having been truly earned. I gave them nothing; they had to earn each win, using their smarts and good strategy. I was in never in favor of random death spells or the like, but fully in favor of their actions and decisions having real consequences. As such, if they failed to think things through and acted impulsively or foolishly, they paid for it. The result was frequent character death; my hope was that for every PC that died, they would cherish the ones that lived all the more.

This was in complete opposition to my buddy who ran his games as if they were movies with our PC's being the stars. In the movies, the good guys win. In the movies, at worst the sidekick might die, but he would do everything he could to ensure that the rest of us got through OK. If things were truly grim, suddenly the cavalry would show up, or the bad guys would decide to capture us instead of kill us where we lay, or we'd suspect him of fudging the amount of damage dealt and given. He'd keep close tabs of how many hit points we had left, and as it got closer to zero, we'd get attacked less and less.

Which is the correct approach? Is there a correct approach? In the end, your style should be determined by your group. After all, the whole reason you're playing is to ensure they have fun. If your group loves the sense of heightened danger, they'll get frustrated with never actually having death be a real possibility. Conversely, if your group love to develop their characters more than anything, love long term campaigns where the story is the most important part, then they'll get no end of frustration at dying every time they mess up.

There is no right or wrong answer to how brutal you should be as a DM, unless you fail to please your players. I eventually stopped being the 'Murder DM' because I realized my players were no longer investing themselves in their PC's, knowing they would soon die. I didn't become a 'Movie DM' either, however; death is still a very real possibility in my games, but I'm much more inclined to throw the players a bone unless they really, really mess up. Then? It's choppy choppy time.