Rather than just complain about how difficult high level combat is in D&D 3.5, my gaming group's decided to do something about it. We've created a playtest group who's willing to put in the extra effort it takes to play a high level game ... and to figure out what, if anything, we can do to make the process work better.
Our first crack at this was the 15th-level one-shot "The Devil-Haunted World". The former temple of the evil god of war is up for auction, in hopes that the buyer will raze the structure and put something productive up in its place. The Cult of the Iron Mask, fanatical followers of the god, have other ideas -- on the day the gavel falls on the auction, the Iron Masks create a great magical iron chain that stretches from the Prime Material Plane to one of the Nine Hells! Their plan is to unleash a diabolic envasion that will enable their cult to conquer the city. To prevent their arch nemesises -- the followers of the good and chivelerous god of war known as the Invincibiles Guild -- from interfering, they erected a barrier keeping out all lawful good individuals.
Thus, it falls to our heroes, some of the most chaotic and powerful adventurers in the city, to breach the shrine's magical defenses, travel to the Nine Hells, and break the chain binding it to the world.
Epic Fights, Reasonable Duration
This was a combat heavy playtest, and I'd planned for three major encounters: the initial battle with the devils and Iron Mask cultists protecting the Chain to Hell, a second fight inside the hellish shrine that lay on the other end, and the final conflict with the horned devil guardian.
It didn't quite work out that way. After a role-playing encounter in which our heroes talked and intimidated their way past the Invincibles Guards at the fallen shrine's gates, our heroes launched into battle against the chain and barbed devil defenders. The party's bard unleashed a powerful mind-affecting spell that cut through the barbed devil's defenses, causing them to flee the battlefield in terror ... right through the chain portal.
After finishing up diabolic resistance (and taking out the remaining cultists) the party pursued the fleeing devils right into the otherworldly shrine ... and pitch darkness.
The horned devil, alerted to the attacking adventurers by its fleeing minions, was read for them, and suddenly the night's big combat was underway. Combined, all this took about four hours for us to get through, which is longer than I would have liked, and cut short the exploration of the hellish shrine.
Lesson #1: Game Prep is the Mind Killer
Going into this first playtest I'd been lulled into a false sense of preparedness by the simplicity of putting together monster encounters for D&D 4th Edition. Writing the scenario outline was easy enough, but I'd forgotten just how long it takes to put together solid statblocks for a high-level 3E game.
The problem is this: almost every monster in 3rd Edition uses the same rules as the players do. They probably have a few unique abilities of their own, but also make heavy use of the same feats and spells as players do. This is all well and good -- it allows you to have monsters that are every bit as complex as their player character opponents.
But in order to keep combat moving at high levels, you have to know what all those abilities do. As the game master, you can't afford to let the game languish while you look up some spell to figure out what it does, how much damage it will do, etc.
That means game prep, and a lot of it. The aforementioned devils (Chain Devils (CR 6), Barbed Devils (CR 9) and the big villain a Horned Devil (CR 16)) each had a number f spell like abilities. I spent hours cobbling together abridged power blocks listing ranges, Difficulty Classes, and damage for each of their abilities.
The most important lesson though, is that I need to focus when doing high level game prep. It's tempting to do this while half-watching TV, but I think that stretched out this process to 5 or 6 hours when it could have been done in two if I'd concentrated.
Lesson #2: Have a Plan
Borrowing a page from the later Monster Manuals and Dungeon magazine, I also mapped out three rounds of possible combat so I wouldn't need to think up a battle plan on the fly. Of course, no plan survives an encounter with players, and these plans were quickly thrown out the window, but it was a good way of figuring out the monster's capabilities, and how they might work well together.
Given that monsters often havve life expectancies measured in rounds, it's a good idea to know exactly what they're capable, and what they might do, rather than delay the game by learning on the fly.
Lesson #3: Start Early
On the player side, we discovered accidentally that starting in the afternoon is better than starting in the evening, and Saturdays and Sundays are better than Fridays.
We started our playtest at around 4 p.m. on Sunday, with people arriving around 3 to review their characters. We scheduled it at this time because this is a side event to the main campaign, and we didn't want to throw off our weekly Friday game with this one shot. We choose Sunday afternoon because everyone could make it, and we didn't want to have the game run too late, what with all of us having to work the next day.
It turned out to be a stroke of genius. Playing on Sunday, after already having played on Friday, meant that everyone had already decompressed from their long work week. Starting 2-3 hours earlier than our regular game time meant that we were all fresher, which made focusing on the more complex rules of high level play much easier.
Lesson #4: Player Prep
As a DM, it's a good idea to give players some idea of what they're in for. This can be as simple stating that they're going to be going up against extraplanar enemies, or it can be the adventure hook that allows them to do some initial out-of-game information gathering (either via your group's message forum or e-mail with the DM).
This plays into Lesson #4, which is Player Preperation. I think the single best way of speeding up high-level combat on the player side is for players to come to the game prepared. They need to know what their characters' capabilities are, how their most popular abilities (be they feats or spells) work, and have a general idea of how their character will play in combat. If an epic level barbarian is going to be in the game, for example, than players need to figure out all of their bonuses from barbarian rage ahead of time. Similarly, if a fighter is going to rely on power attack to slaughter enemies or combat expertise to deflect uber attacks, then they need to do the math ahead of time.
Prepared players greatly speed up combat because they, like the DM, have a battle plan. More importantly, knowing what their characters can do (and doing any necessary calculations ahead of time) means there will be less lulls at the table, which in turn leads to a greater sense of action and urgency during the game (which is exactly what you're looking for in an epic battle).