My very first DM was like this. When I started DMing, I asked him for advice. He said, "You can either build the dungeon for the players, and play it against them, or build it against the players and play it for them." I suppose a true antagonist DM would both build and play the dungeon against the players, but that sounds like a lot of TPKs.

I usually go for whatever makes the best story. In our current game, that usually means screwing over the players. But I tend to do it story-wise, not mechanically. Sure, you can beat up the goblins that captured your friend.. but that means that your other friend will die from the poison, because you'll be beating up goblins instead of getting the antidote.

Yeah, I had a couple of DMs like that when I first started playing back in the mid 90s, and to be fair it really was a lot of fun to just focus on outsmarting each other. Unfortuntaly that sometimes turned into sniping or arguments...

Overall, I think that style of DM was bigger in the past, and the "enabler-DM" came to the fore after 3E was released. I like a mixed-style DM, I guess. But I don't really know anyone who plays this way anymore.

I think antagonist DMs tend to get spawned when a gaming group arises spontaneously without coaching or any experienced members, and the new DM hasn't quite realised that killing the party isn't the way that they 'win' the game. They gradually learn a more cooperative play style or else get de-selected from the meme pool when their players desert them.

Most groups these days tend to form around one or more experienced players, I think. So antagonistic DMs are a bit scarce now.

In my early days of gaming in the late 70's most other referees I knew were either Pure Sandbox (typically coming from a wargaming background) or Actively Antagonistic. But then, the players were often pretty antagonistic too. To a certain extent it was all regarded as 'Good Clean Fun'. That's why you never trusted a half-orc Cleric in 1e AD&D - everyone knew they could be a multiclassed as an Assassin and just waiting for the right moment to cause havoc. Seriously, you never, ever let those guys stand behind you.....

I'd call myself mixed-style, I guess. A PC can certainly get killed by the right combination of stupidity and bad luck in my campaign. But it doesn't happen very often.

I know a GM who is actively antagonistic and her players love her, but like every GM style, what works for some doesn't work for everyone ;)

Antagonistic is probably not the correct term to use: Nearly all GMs are antagonistic - it's part of the job since being a GM means being the opposition or a conflicting situation. If you're not being antagonistic you're play a conflict free game which is not what most groups are doing.

A better term would probably be "competitive" as in viewing the game as a Player vs. the GM competition. There's absolutely nothing wrong with that style of GMing IMO as long as everyone in the group is aware of the situation and wants that style of game. Competition doesn't need to be bad and in many cases is exactly what the players want although they may not be aware of it: The most satisfying challenges are those where we feel something is at stake and when it comes to "traditional" RPG themes, that something is usually our characters' lives.

For example, in most 4E games I run I tell the group right at the start: My job as the GM is to kill you. The hostile creatures you meet are not your friends and you can expect no mercy. The point of this approach, for me, isn't to be a jerk but rather to give the players exactly what they want: A sense of danger and excitement where their very lives depend on their wits, luck, and skill. If you're a GM in this sort of game and aren't out for blood you may as well put your dice back in the bag and play diceless or start fudging rolls to keep the supposed heroes alive.

I would agree: I don't think in most games it's to anyone's benefit for the GM to simply kill PCs simply because he/she can. You do run into those types of GMs but they tend to either be jerks or simply don't understand the rules. Obviously game balance is a critical piece of this, and as you mention, appropriate challenge levels are one of things that a GM needs to keep in mind. That, IMO, is one of the best parts of 4E - they appear to have done a very good job defining levels so that a 4th level solo represents a very tough, but fair, challenge to 4th level characters. That makes creating a competitive, yet fair, encounter actually possible. A lot of other traditional RPGs, including past editions of D&D, didn't do a very good job at this and you could easily end up creating an encounter that was way beyond a the characters' abilities to handle even though the #s said it should work.

John Wick's book Play Dirty is a great discussion of how to be a very competitive GM and have your players love you for it. Many people misinterpret John's approach, assuming he just liked killing PCs, but at its heart what the approach espouses is putting the PCs through the wringer, using everything you can against them (including their own family), to put them in the position that if and when they succeed the players end up with a truly gratifying outcome. Ultimately his approach is about doing this through the story rather than relying on individual encounters to define success: Thus it's sort of a "the war is what counts, not the battle" approach.

P.S. - I didn't get the impression that you were suggesting GMs should fudge rolls.

However, I do think that the fudging of rolls often starts when a GM tries to avoid "being the bad guy" or sets up a situation where failure will ruin everyone's fun or kill the scenario's progress (i.e., the proverbial "you didn't find the secret door" problem). If you (as in the reader, not specifically the U20 blogger) find yourself regularly fudging rolls to keep players alive or keep things moving, you're either playing the wrong RPG or you're creating conflicts and tasks which are pointless. In RPGs, players should always fail forward - in other words, failure at a task should always create some sort of twist to the situation, an interesting complication, an inspiring moment, or a new challenge. In other words, failure should always be interesting. If you're in a situation where failure will stymie the group or story, then there should be no conflict or roll - success should be automatic.

I played a Vampire campaign with a very "me against you" kind of GM (2000 and after). He would do everything to: 1) make his NPCs the 'heroes'; 2) kill/hurt/maim our PCs; 3) never allow any PC to do anything important during the campaign.
The only PC that lived through the campaign NEVER did anything important. He would just stay quiet, even when NPCs bullied him and would do everything that the NPCs told him to do (really, everything, it was humiliating).
All the others PCs died at some point. I lost two PCs, both times right after I outsmarted the GM and did something important. The first time I outsmarted and humiliated one of his favorite NPCs. Later, Nosferatu would appear everytime I did something against the law, till I was hunted, killed and had another PC (the 'survivor') diablerie mine PC (during a session I couldn´t play).
Later, I (with another PC) outsmarted two vampire factions and start to play one against another. Later, the GM send me an e-mail after the session, telling me that my PC was killed while sleeping. "And don´t come to next session". Just like that.
It´s funny now, but I was really angry after the last one.