D&D 5E Need help figuring out the crunch behind this zombie siege

I'm writing a free adventure module and I'm stuck on a Chapter that involves a zombie siege.

The setup is this:

The PCs (level 2/3)are in a town (population 1,000) when they hear from newly arrived refugees that a horde of undead are rampaging through the countryside and are heading this way. They've got ~2 days to prepare.

Assuming they make a stand and fight, this is what they've got to work with:

- the town has a shallow moat and is walled off, with only one gated entrance
- 30 trained fighters in the town guard, have both swords and crossbows (probably MM guard stats)
- 2 expert militia fighters (MM thug stats)
- 3 expert hunters skilled with longbows (probably MM scouts)
- the head priestess (MM priest) and four lower ranked clergy (probably custom stats to be 1/2 CR each)
- enough weapons to equip ~100 commoners in the case of an emergency

The PCs decide how to use the village's defenses.



They'll be up against:

- ~600 zombies
- 3 stitched abominations (MM ogre zombies) that are good at breaking down gates/walls
- the necromancer leading the horde (MM cult fanatic)
- possibly skeleton archers

The necromancer sends the bulk of the army at the gates led by two abominations. She sned the third abomination and some zombies at another wall. She hangs back out of arrow range with a handful of zombies.

Since they have prep time, I want to award the PCs for taking steps to prepare. Some mini missions they could do:

1) The holy wards along the walls have waned in power. A character proficient in Religion can attempt to help the priests imbue the protective magics in the walls once more. If they're successful, , the zombies cannot attack/scale the walls.

2) Boost the morale of the people. If they do, the villagers get a small bonus in combat.

Other creative things that make sense.



Then my problem comes: what system should I use to describe the actual siege?

One option is using the new Mass Combat Rules, though I myself don't really grasp it.

On the total opposite end of the spectrum, I could handwave any combat mechanics that don't directly involve the PCs and just focus on the fights they are part of. There's a breach, go help, fight those guys, fight the necromancer, etc.

Not sure what to go with. Any suggestions?


EDIT: Current setup

Village Fortifications:
- A 10 ft. wide moat encircles the village. The shallow water acts as difficult terrain.
- A 20ft tall stone wall encircles the village. Units can walk on top of it. A 10-ft.-by-10-ft. section of wall has AC 17, HP 40, and a Damage Threshold of 8
- A 15ft wide gate is the sole entrance into Shadowgrange. It’s made of wood reinforced with steel and has AC 16, HP 35, and a Damage Threshold of 2
- Any make-shift barricade made by the villagers is primarily wood and has AC 15, HP 15, and no Damage Threshold

Village Defenders:

Solos:
- Each PC; can be commanders
- 1 priest, Priestess Flora; can be a commander
- 2 thugs, the cathar commander Levi and retired commander Eckhardt; can be commanders
- 3 scouts, Silvia, Rosa, and Ann; can be commanders

Stands (10 identical creatures):
- 4 guards
- 10 commoners
- 1 clergy (treat these as Priests without Divine Eminence, no 2nd or 3rd level spells, and only 10 HP)


Zombie Horde side:
Special Traits:
- The undead do not fear their own destruction and auto-succeed morale checks
- Undead Fortitude: zombies with this ability can only use it once.
Solos:
- 1 cult fanatic, Rineta Smitt; can be a commander
- 3 ogre zombies; can’t be commanders
Stands:
- 40 zombies
- 2 skeletons


Village Objectives:
- destroy an ogre zombie solo = 1 VP, max 3
- destroy all skeletons = 1 VP
- destroy 100 zombies = 1 VP, max 6
- defeat the cult fanatic = 3 VP
- protect the gate = 1 VP per round if the village has two or more stands adjacent to the gate if it has not been reduced to 0 hit points, and if no enemy stands or solos are within 2 squares of the gate
- protect the breach = 1 VP per round if the village has two or more stands or solos adjacent to a breached wall/gate and an enemy stand or solo spent the round attacking through the breach


Horde Objectives:
- destroy a wall = 4 VP
- destroy the gates = 4 VP
- defeat a PC = 1 VP
- defeat 4 stands = 1 VP
- defeat 3 non-PC solos = 1 VP
- overrun the village = 1 VP per round if the horde has ten or more stands inside the village walls


Village Tactics:
- follow PC commands
- PCs given rings that permit telepathic communication amongst them and the other solos/commanders


Horde Tactics:
- the main unit comprised of 2 ogre zombie solos and 33 stands of zombies heads for the gate
- a unit of skeletal archers (2 stands) moves behind the main unit to fire at defenders on the walls
- a secondary unit of 1 ogre zombie solo and 5 stands of zombies heads for a back wall, regiment
- the cult fanatic commands her own unit of 2 zombie stands and hangs back until the Villagers acquire 5 VP, and then she moves into combat

You could have players get more mini missions based on their classes. Such as warrior types could teach fighting, clerics could boost morale, mage types could put on a magic show to distract folk of their upcoming horror... Have some bar bums leave their bar and partake. Party face could convince some horses for use from the stablemaster.

On a situations like that, there are runners, hiders and people who want to protect their own valuables at first. You can work from that.

This scenario is always fun.

In my experience, they key to achieving that fun is to keep the focus on the PCs.

Describe what happens to the town, let the zombies break through at some point so the PCs can plug the hole in the defenses, then have a final surge that flows into town and give the PCs chances to save townspeople while being nearly overwhelmed.

Really play up on the tension and be sure to note where the townspeople are doing things the PCs encouraged/taught them to do that are helping stem the tide.

Wait to see if the PCs will counterattack. If not, bring the villain to them for the fateful showdown.

Good luck!

Don't forget the role-playing side! Try adding a morally difficult NPC, like a priest of Hextor (for Greyhawk). Evil people have friends and family too. And they want to make a name for themselves. The NPC should be of lower level than the PCs - or the same level if to be played by a drop-in player. A foil, rather than an opponent. Or you could have the NPC be an evil fighter-type who isn't so sure about her moral compass any more and PCs get the opportunity to turn her to Good.

On top of that, have a handful of encounters with the people of the town. Have an encounter with the guards, where they are talking about the fear of facing down an unstoppable horde of the dead. Give the PCs a chance to influence them on a personal level, while also giving them a few faces and names among the NPC guards. Have an encounter with some children, who are excited about 'participating in a great battle'. Give the PCs the difficult choice of whether or not to give children slings and put them on the walls. How many extra soldiers would that be? Can they have them up there, and then pull them out of harm's way when the dead get to the walls?

I remember fighting ~12 zombies in Lost Mines of Phandelver without radiant damage. That town is screwed by the ~600(!) zombies alone.

The UA rules would actually be of great help to you, even if the defenders are almost entirely too small to make good use of them. What part are you having trouble with?

PnPgamer said:

You could have players get more mini missions based on their classes. Such as warrior types could teach fighting, clerics could boost morale, mage types could put on a magic show to distract folk of their upcoming horror... Have some bar bums leave their bar and partake. Party face could convince some horses for use from the stablemaster.

On a situations like that, there are runners, hiders and people who want to protect their own valuables at first. You can work from that.

Click to expand...

My mini missions so far are as follows:

1) Anyone proficient in Religion can help power up the protective wards on the walls. If successful, no zombies climb over.

2) Anyone can attempt to boost morale. If successful, the NPCs fight harder.

3) New recruits (commoners) don't know how to use their weapons. If someone shows them how, they fight without disadvantage.

4) Anyone can go scout the zombie horde. This gives them a better indication of numbers and direction they're coming from.

5) Deserters and whatnot can be straightened out.

sanishiver said:

This scenario is always fun.

In my experience, they key to achieving that fun is to keep the focus on the PCs.

Describe what happens to the town, let the zombies break through at some point so the PCs can plug the hole in the defenses, then have a final surge that flows into town and give the PCs chances to save townspeople while being nearly overwhelmed.

Really play up on the tension and be sure to note where the townspeople are doing things the PCs encouraged/taught them to do that are helping stem the tide.

Wait to see if the PCs will counterattack. If not, bring the villain to them for the fateful showdown.

Good luck!

Click to expand...

Thanks! I plan on having a main attack at the gate and a secondary attack on the wall itself. It's likely one of these defenses will fall unless the PC is there to help. Afterwards they'll definitely have to take on the necromancer.

Quartz said:

Don't forget the role-playing side! Try adding a morally difficult NPC, like a priest of Hextor (for Greyhawk). Evil people have friends and family too. And they want to make a name for themselves. The NPC should be of lower level than the PCs - or the same level if to be played by a drop-in player. A foil, rather than an opponent. Or you could have the NPC be an evil fighter-type who isn't so sure about her moral compass any more and PCs get the opportunity to turn her to Good.

Click to expand...

As soon as the refugees say there's a zombie horde coming, a council meeting is called where the PCs are invited. I'll have each council member have his/her own solution. Ultimately can advocate a plan, but they'll have to convince everyone to get on board with them.

MortalPlague said:

On top of that, have a handful of encounters with the people of the town. Have an encounter with the guards, where they are talking about the fear of facing down an unstoppable horde of the dead. Give the PCs a chance to influence them on a personal level, while also giving them a few faces and names among the NPC guards. Have an encounter with some children, who are excited about 'participating in a great battle'. Give the PCs the difficult choice of whether or not to give children slings and put them on the walls. How many extra soldiers would that be? Can they have them up there, and then pull them out of harm's way when the dead get to the walls?

Click to expand...

Oooh, the children and elderly is a fun dilemna. You get 100 capable commoners, but you can get much more if you put a weapon in anyone's hands. What do the PCs do?

Leatherhead said:

I remember fighting ~12 zombies in Lost Mines of Phandelver without radiant damage. That town is screwed by the ~600(!) zombies alone.

The UA rules would actually be of great help to you, even if the defenders are almost entirely too small to make good use of them. What part are you having trouble with?

Click to expand...

Just having trouble in general. I'm not sure if I have this right.

Would this be accurate?

Village Fortifications:
- moat circling the village, 10 feet wide, shallow water, difficult terrain
- 20ft tall wall, units can walk on top, auto-hit, 300hp?
- 20ft wide gate, auto-hit, 200hp?
- any make-shift barricades, auto-hit, 50-100hp

Village Side:
- PCs = each a solo, can be commanders
- 30 guards = 3 stands of guards, work as regiments
- 2 thugs = 2 solos, can be commanders
- 3 scouts = 3 solos? Or do I let the PCs find 7 more scouts and they become a stand? Work as skirmishers
- 100 commoners = 10 stands of commoners
- 1 priest + 10 clergy = 1 solo and 1 stand


Zombie Horde side:
- ~600 zombies = 60 stands
- 20 skeleton archers = 2 stands
- 3 ogre zombies = 3 solos, can't be commanders
- 1 cult fanatic = 1 solo, can be commander
- undead are fearless in battle, auto-succeed morale checks

Am I doing it right?

You have it right.

The big concern for balance's sake is the zombies' ability to stand back up after being killed. If all 600 zombies have that ability, the townsfolk are well and truly screwed (and it will also be a bookkeeping nightmare at the table). On the flip side, skeletons being resistant to piercing damage makes them very frustrating to fight at range.

I playtested the battlesystem rules in their earlier incarnations. PCs can fight off much larger forces with use of choke points. You could put a river a day's ride from town where they can hold a bridge and whittle down the numbers. Also, ranged attacks are extremely powerful in battlesystem, and this is where the PCs will have the edge. The skeleton archers will be the biggest threat to the PCs, at least until the walls and gates come down.

Good points. I'll remove undead fortitude, it's not needed for this. Maybe 600 is still too much. Skeletons have no resistance to piercing that I'm aware of.

Personaly I would leave the zombie fortitude as is just switch the zombies with the skeletons, have tons of skeletons and a strike force of zombies, the commoners could handle the skeletons better than fighting zombies, leave the zombies to the PCs and milita.

Warder