Biggest combat/encounter you've run?

[Kheti sa-Menik]

Biggest battle was on the top desk of a ship:

3 PCs (4th level) + one PC's animal companion
1 NPC ranger
1 NPC ship captain (expert/fighter)
1 NPC master at arms (expert/warrior)
3 NPC chief bosuns (experts)
27 NPC sailors (mostly experts with some commoners)
1 NPC ship's doctor (expert)
8 NPC passengers (experts, commoners, aristocrat)

vs

3 vampire spawn
1 master vampire

(vampires/vampire spawn were my on templates, less flashy powers than standard D&D, little more concentation on brute force, like Buffy/Angel-style vampires)

Three vampire were dispatched without much casualty, although a desperate grapple in the sickbay between the NPC doctor and one PC almost ended in tragedy.

When the master vampire entered the fray, things changed...the NPC crew grew cocky at their defeat of the spawn so charged the weapon-less master vampire.....who had levels in fighter, concentrating on unarmed combat.
As each NPC passenger/sailor charged him and fail to hit, he easily fell three opponents on his turn with his bare hands.
The PCs were...nervous as the NPC bodies stacked up like cordwood.
Finally, the NPCs failed their morale check and ceased attacking, taking up defensive positions.

I can it fairly straightforwardly. PCs, NPC ranger, NPC ship captain, NPC master at arms, and master vampire all had their own inits. Everyone else I grouped initiatives: bosuns and doctor went at the same time, passengers at another count, sailors at another initiative count, and the vampire spawn at another.
11 initiative scores weren't hard to manage, especially with the Combat Pad-magnet thing Paizo sells. Some turns, like the 27 sailors, took longer than others, but it seemed like a fast paced battle.

 

[Brakkart]

The biggest battle I've ever run hands down was in my Rise of the Snakemen campaign when the party were taking a "short cut" through an old dwarf hold under the mountains to get to a ruined Yuan-ti city in the jungles on the other side. There they ran into a hive of Clockwork Horrors and the resulting battle ran for several game sessions, lasting a grand total of 59 consecutive rounds of combat!

The PC's were all about 7th level at the time as I recall and there were 6 of them vs about 40 Electrum Horrors, 6 Gold Horrors and 1 Platinum Horror. Amazingly none of the party died, though the spellcasters were all out of spells higher than 0th level by the end of it and there wasn't a healing potion left to the group. It is still one of the most talked about events in my gaming groups history and was an absolute blast to run!

 

[Silver Moon]

Back in my gaming group's early years (mid-1980's) I had one combat encounter with 14 players, several of whom were running two playing characters, as well as 25 ally NPC's. I had over 300 bad guy miniatures on the table. I had two guests helping me play the monsters and it still took two extended games to get throgh the battle.

 

[logan9a]

I use to roll for 'large encounters' until I discovered that was boring for many of the players. Yes, there is always the one guy who wants all of the NPC's rolled for but him we just slap around some.

After I switched to a better system (HC), I now gloss over the other parts of combat to focus in on 'what are the PC's doing' and 'what are the people they are directly fighting doing'.

Because, in the end, everything else is background.

To answer your question though - before I learned how to be a better GM - the largest fight I ran was maybe 50-75 (I forget) total combatants.

 

[Terramotus]

I ran a number of "mass combat" battles in 3E, but none of them happened until starting at 9th level or so. The end result was that the party mostly inserted themselves into trouble spots, took out huge monstrous enemy combatants, and launched surgical strikes on leaders. Failing that, they blasted mooks into smithereens. But I never actually handled the thousands of mooks as statted out combatants. I mostly told them how the battle was going based on some random rolls I did. I assigned each side a number of d6's, depending on their situation and bounced a bunch of dice. The one with the higher number had the advantage at the time.

What I considered the biggest combat was the final adventure. The campaign had run with the same players for about 2 years of real time, and I had arranged the game to end about 6 months previously in epic levels when the fighter of the group rejoined the army. Well, he was able to come back for one more game, so I made it a doozy. Happened 10 years later in game time, and I bumped all the characters up a few more levels. They were saving their kids this time, as well as the world (again).

In one session, one after another, they faced an opposing party of epic adventurers, a boatload of pseudonatural nasties, a great wyrm red dragon, and for a finale, Orcus from the BoVD. Though he was technically Velsharoon stripped of his godhood, since it was FR - don't ask, it's complicated.

I spent probably 8 hours in prep work for it, and they plowed through it in as many. It was a blast. The fighter was Revivified so many times it was like he was a weeble-wobble.

 

[Darklone]

Biggest battles included between one and two thousand combatants. Mostly mooks and about 60 bigger NPCs.

 

[Jhaelen]

I'm just considering 3E, earlier editions were quite different. The longest battle I've had so far lasted 8 rounds and took over 6 hours to play. It initially involved only 3 high-level npcs (12th level conjurer, 10th level druid, 11th level shadowdancer). During the cause of the combat 32 low level npcs (2nd level warriors) and about 5 summoned creatures joined the fray.

It was a quite challenging encounter for the 7 pcs (average level 10). This was mostly due to the environment and because the two main pc spellcasters were busy casting dispel magic 50% of the time.

I've prepared a pretty big encounter for one of my next sessions:
An orc war party with a total of 80 individuals that will attack in several waves from different directions:
1st to 3rd wave: 12 L3 barbarians, 3 L4 marshalls, 2 L5 fighters, and 1 L7 druid (EL12)
4th wave: 18 L3 barbarians, 3 L4 marshalls, 3 L5 fighters, 1 L7 druid and 1 L8 warchief (EL13)

It's something I've long wanted to do, and I hope it will be sufficiently challenging to make a memorable fight.
- All orcs have at least a single Barbarian level and because of stacking effects from buffs, auras and class abilities even the lowliest have a good chance of hitting the pcs and should be able to survive one or two (if they're making their saves) AE spells.
- Since they'll be attacking in staggered waves, the pc spellcasters shouldn't be able to take them all out before they can become a threat.
- It will also be difficult to make out, which of the orcs should be primary targets since they're mostly equipped identically.

We'll see how it goes

 

[NewJeffCT]

Biggest battles included between one and two thousand combatants. Mostly mooks and about 60 bigger NPCs.

I hope you didn't roll for all of that?

 

[Drowbane]

3e. Two PCs versus a 150 "normal orcs". The elven ranger 3 / rogue 3 got dropped to negatives and stabilized and my dwarven cleric 6 stood over him with his large shield and war-axe and dropped them as they rushed in... until the dwarven calvary (my cohort, a barbarian1 / fighter 4, & warrior - followers) arrived (we'd decided to scout ahead... or something).

Just two players and a DM, wasting time and rolling dice.

My dwarf was down to around 25 hp at the end.

 

[blargney the second]

I ran a grand melee with about 50 combatants in a 3.5 game. To simplify things a bit, I used DDM skirmish cards for their stats with D&D rules still in effect.