Many people have asked the following question:
There is no easy answer to this question. Why is there so much violence in roleplaying games? Why, indeed, is there so much violence on TV, and in movies? There seem to be two answers which apply to roleplaying, which, if they do not justify, at least help to explain.
Violence as dangerous excitement
There can be no doubt that man is a species that has evolved for violence. Although the threat of violence and danger produces fear, it also produces excitement. It is for this reason that so many people enjoy dangerous sports such as mountain climbing, because the threat of danger creates a thrill that more intellectual pastimes do not appear to do. Similarly so many people take up crime, not only because they are in need, but because the violence of crime can, in itself, be attractive.
For most people neither life-threatening sports nor violent crime seems a good way to get a thrill, fairgrounds are more popular. Perhaps the beast way, though, is to experience the danger vicariously, through books or films.
Roleplaying is, of course, the ultimate kind of vicarious enjoyment. The character may die, or suffer a terrible fate, but the danger does not pose a threat to the player, who is safe in the game, outside the game-world. Nevertheless, since the player identifies with, or is trying to imagine himself in the place of, the character, she does feel the thrill and fear produced by the threats to that character. Since roleplaying is the safest way to get your thrills it is natural that the players should indulge in the most severe threat of all, of death and violence. It is hard to really feel the threat of poverty, or hunger, or age, when it only affects the character that you are playing, but death or violence is much easier to perceive, and therefore far more effective. Indeed it is one of the curses of horror RPG's that it is so much easier to produce violence and the fear of death than it is to conjure up more subtle terrors.
With the threat of violence to the characters it is no wonder that the characters react in the same way. If your character is threatened with being eaten by a monster then you will most likely attempt to defend it, and since a fight to the death is more exciting than a brief bout, that is what you get, and violence becomes important in the game.
To be sure, of course, there are other ways to produce tension and threat, through subtle plots, hard work creating real emotions, and a lot of time, but not every GM is a budding writer, and it is hard to be certain that these other methods are really any better than outright violence. Is it really worse to have the characters attacked by monsters than to attempt to ruin, bereave, or terrify them?
Violence as the release of tension
It is a well known fact that lots of people play contact sports to release tension and built up aggression, aggression generated by pressure, worries, and problems. For the same reason people enjoy violent films and books, but these can only go some way towards really releasing aggression, because they are essentially passive.
The ideal way of getting rid of aggression, indeed, is to use it, actively, somewhere where no one can possibly get hurt. A roleplaying game is that perfect outlet. The aggression of the players is vented on imaginary monsters and threats, foes and traps. It does not go on other players (Though see PK'ing and article on Winning in RPG's), or on the GM, but on the puzzle and challenge of the game which will, in turn, produce a cathartic closure when the monsters are finally overcome. Naturally the most common analogue of violence inside the world of the game is violence by the characters, which uses up, rather than creates, the aggression of the players.
It is surely for this reason that most campaigns tend to end with a victory for the characters. Even though some characters may die along the way they can be replaced by other characters played by the same players, till the threat is conquered and the aims achieved. It is very seldom that a game sets up some target which the characters totally fail to get to, and are instead destroyed and defeated, for where is the fun in that. Certainly plans may go completely wrong, things may fall apart, and it may seem that all is ruined, but the perpetual hope of a better ending makes the game worth playing. See also When to kill off characters