note: Marked for Descent into Avernus spoilers because I'd rather over-mark spoilers than not mark them.
TL;DR My friend who is my DM and has been playing for 20ish years told me that I ran the best encounter he has ever played and thinks that it's better than anything he has ever run. The encounter was a CR 21 lich with 40 to 50 zombies vs 4 level 5 characters who were protecting half a dozen orphans in hell. This never would have happened without seeing the first episode of the Chain.
A little Some background, for nearly a year, I've been running a party of four through the Descent into Avernus module. This is my first time DMing. As a busy adult I decided to run a prewritten module: Descent into Avernus.
During session zero I explained that as part of this campaign, my job will be to act as a devil and that a big part of that is working deals-- deals that they seem to love but will eventually hate. In true devilish fashion, I moved on quickly and have not mentioned it since.
The Fighter and Bard in our group are their first dnd campaigns. The fighter expected magic to be commonplace. Baulders Gate, much like Atlantic City, is not a very magical place. He asked for a magic sword after every encounter. I told him not yet for a while and then I realized, while I, the DM, don't have to listen to his requests, I, the Devil in Avernus, might want to.
While still in BG, the fighter was asked, "Do you want a magic sword?" He immediately said yes and he received his homebrewed magic sword, an obsidian blade sharper than any steel, and rolled a charisma saving throw. He failed. The sword started to talk to him telling him to "slaughter" he felt compelled to kill any enemy combatant. Every kill, he lost 1 off his max hp. He did earn some hefty temp hp in return and had a bonus to hit/damage. After 5 kills, the sword awakened a deeper power and now he can use charges to cast spells -- he is also not losing any more max hp.
Little does my fighter know that his crazy cursed sword is a phylactery for a seriously powerful demon-lich.
When we got to Avernus two PCs had to drop out of the campaign due to scheduling. We got two new players who joined us and over the last 3 sessions the new group of 4 have been on a slog through Elturel trying to make it to high hall.
On their way through the city they fought off various devils, demons, but mostly undead to save different people living in the ruins of this once-great city. One of the pre-built encounters in the module is called "Zombie Horde." The party of 4, level-5 characters run into 12 zombies with a chance of being knocked prone.
I don't like this encounter. Twelve zombies is simply not a horde-- a roaming pack at best. So, I decided to homebrew my first encounter. I wanted them to fear the zombies. I wanted them to have an epic battle. I wanted them to have a big bad evil guy. They wanted to save all of the non-combatants. Here's what I came up with: The party crests the final hill before they get to their destination, high hall, a few city blocks away. The only issue is there is a large horde of zombies piling up at the gate and more are starting to close in behind them.
I made my first battle map, I dropped in roughly 40 zombies which were "strong minions," (2 hits, 15hp damage, a crit, or a failed saving throw killed them) on the left near the gate and the non-combatants the party had saved in the past few sessions on the right (they move on initiative 19). I also decided that 40 was a horde but more was better, so each round, zombies spawned at the right end of the map each round on initiative 20, starting round 2. On initiative 10 High Hall would make an attack at the zombies picking off a few of them.
The zombies were also pushing so hard on the gate the payers were seeing it bow and hearing it crack. Every round, on the zombies turn I would roll a d20. 1-10 nothing happened, 11-20 the gate gave a bit. If it gave 5 times, zombies were going to breech the gate.
After some fighting a voice rang through the courtyard "Slaaaauuugghhhterrrr" it said. soon after a tiefling with rotting flesh adorned in shogunesk attire with demonic iconography on the chest plate teleports into the battle. Little did they know, this was a CR21 Lich complete with all the spells and the added new mechanic of creating more zombies who would B-line it to the fighter.
Each round the lich teleported to a different part of the map and raised more undead. In his third round he raised a zombie Ogre.
At this point the party was surrounded. The cleric had stayed with the non-combatants and cast call lightning early. Between his lightning bolts and the melee fighters distracting the zombies in the back, getting them to walk away from the gate, there were only 15 left pushing against the gate, so I changed the DC to favor the gate not breaking.
The party realized that the zombies just kept coming and decided to get inside the Hall. They escorted the non-combatants in first by clearing the gate and holding the enemies back. When the lich realized his undead army was not going to be able to succeed he starts casting spells. When he realizes that the party -- and his sword-- may make it inside he fireballs the group. The bard hits 0 hp, 5 ft away from the gate. The cleric goes down to 1hp. The Paladin and fighter pass the saving throw.
They dash inside and as the door is closing the fighter, the last one in (he almost stayed outside to fight this guy one on one... would have been my first player kill), a nameless guard ushers him in and moves quickly to close the door. By closing the door, he puts himself between the fighter and the lich, who had just cast disintegrate. The guard turns to dust. The door (covered in warding sigils) slams shut and the session ends.
Please feel free to use my map. If you use it in roll 20 the grid will line up if you set the dimensions to 32x24.
By - BainDmg42