D&D 5E Balancing Mummy Lord fight with CR

[DurrandDurr]

I have a party of 4, level 13 players. One is a Paladin who has an aura that prevents being frightened as well as a +1 Sword. Two characters can do fire damage. The rest of the party is a Druid, Sorcerer, and Bard. They wipe out solo monsters quickly; and use Banishment. The Paladin did about 80 points of damage in one attack on a nat. 20, and two of the party members can cast fire-based attacks. I think the Mummy Lord wouldn't last more than 2 rounds solo.

I'm thinking of giving the Mummy gold-plate armor that is fused to the mummy's body that grants fire resistance (removing the fire vulnerability), but adds vulnerability to lightning (gold is conductive) to counter meta-gaming knowledge. That might let it last a couple more rounds.

Adding more monsters to this fight seems best, but not sure how many to add or what type Thematically I was considering regular mummies, an Air Elemental or a couple undead constrictor snakes (looking like Bone Naga but without the lore). Would 2-4 more mummies do it, or is that overkill?

 

[Sword of Spirit]

In my opinion, you want to have at least as many monsters as PCs. And the weaker the foes the more of them. So if you want to play it safe add all those plus one or two dozen “lesser mummies” (zombies with fire vulnerability and some mild offensive boost). Feel free to use the mob rules in the DMG if that seems like too many bodies in the fight.

 

[tetrasodium]

I have a party of 4, level 13 players. One is a Paladin who has an aura that prevents being frightened as well as a +1 Sword. Two characters can do fire damage. The rest of the party is a Druid, Sorcerer, and Bard. They wipe out solo monsters quickly; and use Banishment. The Paladin did about 80 points of damage in one attack on a nat. 20, and two of the party members can cast fire-based attacks. I think the Mummy Lord wouldn't last more than 2 rounds solo.

I'm thinking of giving the Mummy gold-plate armor that is fused to the mummy's body that grants fire resistance (removing the fire vulnerability), but adds vulnerability to lightning (gold is conductive) to counter meta-gaming knowledge. That might let it last a couple more rounds.

Adding more monsters to this fight seems best, but not sure how many to add or what type Thematically I was considering regular mummies, an Air Elemental or a couple undead constrictor snakes (looking like Bone Naga but without the lore). Would 2-4 more mummies do it, or is that overkill?

Paladin can do big spike damage but there are a lot of other sources (ie fighter & rogue) that can do almost as big round after round. What is the rest of te party?

 

[iserith]

It really depends on how taxed on resources the PCs are when they get to this fight. If they are fresh, then it probably doesn't matter how many additional mummies you add - they'll get dusted fairly easily with characters at that level. You can basically throw out the CR guidelines at this level if your players have any level of play experience.

I would suggest you give the mummy lord counterspell and have Cast Dispel Magic as a legendary action. Then make sure to use the Lair Action that wracks spellcasters with pain. An environmental effect like bad air or even explosive gases can also put a damper on the fire magic. You could even make the chamber air tight which would be neat - just create some kind of option to get some air in the room like busting down stone doors or something.

Set up the terrain such that the mummy can stay out of the reach of the melee PCs for as long as possible and harry them with spells (keep tabs on concentration) and dreadful glares while mummies, swarms of beetles, or whatever else is thematic whittles them down. The legendary action that allows it to turn into a whirlwind might help with mobility. It wouldn't hurt to give it misty step though. I would also get rid of the immunity to dreadful glare on a successful save.

I can't underscore enough that terrain is going to be your friend here, both in presenting a cool thematic encounter, but also creating a tactical challenge to the PCs. So I recommend spending at least as much time thinking and designing that as you do in picking monsters.

 

[DemoMonkey]

I always have the same advice in these situations. If the Big Bad can't survive a PC nova-strike, make sure they have a decoy to draw all that fire while they strike back from concealment.

If the players burst into the Inner Sanctum and waste the Big Bad because it is standing out in the middle of it wearing a "Fireball Me!" sign, that is bad planning on the Big Bads part for making themselves an obvious target.

 

[jgsugden]

The Mummy Lord is a.) Exceptionally wise, b.) Capable of foreknowledge via Divination, c.) served by 'lesser undead'. It should be as likely, if not more likely, than the PCs to be able to dictate the terms of the battle. A 13th level paladin has about 100 hps. It should also have useful treasure fitting for its former life - including perhaps magic staves, magic weapons, etc....

If your party is very skilled, and uses stealth, they may get the drop on the Undead Mummy Lord and if so, the battle should favor them. If they just blunder in, it should be ready for them and go for the surprise ambush. They should have traps galore in their abode, including ones that take advantage of their lack of need to breath. Remember that undead should know the presence of living creatures in the lair from a lair action every little bit of time.

It has been a bit of time since I had the PCs fight a Mummy Lord, but that group ended up separated and contending with different traps and monsters that tied them up while the Mummy Lord went after them one on one. It wasn't an easy win for the PCs.

 

[Quartz]

I'm thinking of giving the Mummy gold-plate armor

Rather than making the gold armour grant fire resistance, how about making the gold armour the treasure they're there to find? So now they cannot use fire magic because that would melt the gold.

Make some mook earlier have gold armour which succumbs to fire.

The Paladin did about 80 points of damage in one attack on a nat. 20,

That must have pretty much maxxed all the dice.

 

[DurrandDurr]

That must have pretty much maxxed all the dice.

He poured Divine Smite on top of the Crit.

 

[CleverNickName]

Yeah, I agree...that's going to be a very quick and anticlimactic battle. You should give the mummy lord some backup. Have a few Deathlock bodyguards who can cast Counterspell in the room, or maybe a harem of banshees.

 

[DurrandDurr]

It really depends on how taxed on resources the PCs are when they get to this fight. If they are fresh, then it probably doesn't matter how many additional mummies you add - they'll get dusted fairly easily with characters at that level. You can basically throw out the CR guidelines at this level if your players have any level of play experience.

I would suggest you give the mummy lord counterspell and have Cast Dispel Magic as a legendary action. Then make sure to use the Lair Action that wracks spellcasters with pain. An environmental effect like bad air or even explosive gases can also put a damper on the fire magic. You could even make the chamber air tight which would be neat - just create some kind of option to get some air in the room like busting down stone doors or something.

Set up the terrain such that the mummy can stay out of the reach of the melee PCs for as long as possible and harry them with spells (keep tabs on concentration) and dreadful glares while mummies, swarms of beetles, or whatever else is thematic whittles them down. The legendary action that allows it to turn into a whirlwind might help with mobility. It wouldn't hurt to give it misty step though. I would also get rid of the immunity to dreadful glare on a successful save.

I can't underscore enough that terrain is going to be your friend here, both in presenting a cool thematic encounter, but also creating a tactical challenge to the PCs. So I recommend spending at least as much time thinking and designing that as you do in picking monsters.

The bulk of the map is difficult terrain: beach-like sand and fallen rocks. I was trying to think of a sand tentacle effect (Black Tentacles) in the center of the chamber. Or a whirlpool of sand that drags them down (quicksand rules?). I'm a new DM so creating these environmental things is a learning curve.