2. If you are a TPK DM, what's the deal? Why? How does it work?
If you want to place enemies that are a credible threat to players, or actually act like they want to kill the players, then a TPK is possible. Witht eh ECL system, it's not likely, but it's possible:
Here's mine (5th level party, with L4 NPC):
Executive summary
The players got involved in skirmishing with a large (40+) band of Gnolls. The leader of which was slightly above their level. the leader was not meant to get involved in comabt, and the PCs were not meant to take on the entire tribe.
But they did....
The gritty details
Players:
1/2-ling Wiz 5(evoker)
Human Ranger2/Rog1/Cleric of Farlangan 1
Human Ranger 2/Rog3
1/2-Orc Cleric of Obad-hair3/Barbarian2
and an NPC L4 Paladin on a War Horse (NOT a special Mount, Although the party assumed he was)
How it happened:
The ‘scouts’ (The two Rogues) stumbled upon a gnoll war party guarding the moat house from Monte’s RttToEE. One of the Rogues accidentally gave their position away (failed to move silently)
All told there were 40 Gnolls. I broke them up into simple search bands:
5 regular gnolls (2 groups), one gnoll with an obvious signal horn
4 regular gnolls with a CR3 leveled Lieutenant (ranger)
The rest of the Gnolls would stay together, with the Chief (Level 5 barbarian), and other lieutenant (CR3 ranger again)– unless the party threatened the main camp, which would cause the Chief, the other lieutenant, and 3 gnolls to protect the tribe.
The gnolls has some minor potions (aid, CLW, CMW, Enlarge) and the following 3, more powerful magic items:
Quaal’s feather token: whip ->Lieutant#1,
Potion of Fire Breath ->Lieutenant #2,
+1 battle axe ->Chief
The party was putting the smack down on first band of regular gnolls, but failed to address the signal horn. The second search party came, and was quickly down to 2 members, who ran, and blew their signal horn again! Note that they ran back towards the gnoll camp. The third party of gnolls, responding to the signal horn, homes in on the party, and the wizard who had been sneaking ahead invisibly opens up on the lieutenant with Magic Missile (his first offensive spell of the day – he had been conserving). This did not kill the lieutenant, but got his attention – he loosed the Quaal’s feather token: Whip on the mage – who could not wrestle free, and had no Verbal-only escape spells.
Still with the NPC helping, that party was looking ok, and it was only once the lieutenant blew the horn to summon the chief that things got ugly. The party dropped the lieutenant the next round, and there was only a single Gnoll left of all three original hunting parties. He ran and the party chased him 100 or so feet., leaving the wizard behind, for now (they thought).
They ran into the Chief’s band.
The chief had the RUN feat, and ran 200’ ahead of his band (40x5). He provoked 2 AoOs to get into the center of the party. The two rogues tried to flank him, and because he was a L5 barbarian, failed (but still hit him for *some* damage). The chief RAGED, and took his full attack with the +1 battle axe on the Ranger/Rogue in two hands, dropping him in one round (d8+10 x2), proving that CON is always an important stat. STILL things did not look so bad. The party had a single bead of force that they threw at the chief, who took 5d6 and was trapped in the force sphere.
Meanwhile the second lieutenant, drank the potion of fire breath and went to town with it. 3d6 of damage, save for ½ (or none when you are a Rogue) may not seem like much, but to a Paladin in full plate, and a grappled wizard with bad luck, it was ugly. They took all three rounds of it (9d6) – this killed the wizard, the previously injured Paladin, and his Warhose (total damage was 35 – but the last roll was the killer – the other two were average - the paladin went from 12. to -3 in one round).
Now things were looking grim. Two party members faced of against a leveled Gnoll, and 2 Regular Gnolls while the Chief watched, drank healing potions, and grew fatigued.
The Cleric/Barbarian was a strong tank with a low AC. He raged. He dropped one Gnoll a round like clockwork... And then it happened: the lieutenant rolled a 20 to hit and was using light picks as his weapon - that‘s a x4 crit to you and me folks, and it’s easy to confirm a crit vs a shield less raging Cleric/Barbarian 4d4+16 later, the last source of healing dropped with 1 gnoll and the Lieutenant wounded, but up.
The player debated running (he had used his expeditious retreat), but decided to try and tactically circle around the force bubble in an attempt to lure the gnolls away from the downed PCs, so he could RUN in and give the cleric a healing draught. And it almost worked, Trouble is, when you run, you lose you DEX bonus to you AC, which in this characters case, was a LOT (4). He took 2 javelins while scooting over to the cleric, for d6+4, and d6+2, this resulted in 15 points of damage, placing him at -1
End of Line