D&D 5E Death Knight Legendary Actions & Lair Actions

[UngeheuerLich]

Yes. He does not look too strong on paper.
Probably his hellfire blast pushes him to that CR. It is a 20d6 fireball which averages 70 damage in an aoe. That is 140 damage accounting to his offensive CR. The other rounds assume 27x3 damage + 4th level staggering smite which adds average 14 psychic damage and also imposes disadvantage to all attack rolls.

That in return will increase his defenses a bit. In combination with his already considerably high AC 20 + 6 from parry 1/turn will make him hard to hit for your zealot, especially when trying to benefit from GWM.
Assuming +9 to hit from your barbarian, that is only a 50% hit chance without -5/+10, 75% with advantage. Against 26 AC it drops to 20% or 36% with advantage. With - 5/+10 you are down to below 40% against 20 and 9.75% against 26 with advantage.

So probably it depends on who gets the jump on whom.

 

[Flamestrike]

FWIW our tier-4 game just fought a DK (the DM gave him a Scimitar of Speed so it got 4 attacks per round! )

It's just as good without one thanks to its Paladin Smite spells. Staggering Smite alone nets it 4d6 psychic damage on a hit plus the status effects.

Everyone forgets about them.

You're lucky the DM didnt switch one of its 5ths for Holy weapon.

4 attacks, dealing 7d8+Str damage each hurts.

 

[Flamestrike]

Reckless attack hasted zealot barbarian GWM (optimized, but hardly an obscure build) can do over that just by itself.

A 12th level reckless attack hasted barbarian (Str 20, +1 weapon) is at +5 to hit (with advantage) vs an AC of at least 20-26, with three attacks.

He needs 15's and likely hits once, and its parried. Even if he lands one, its around 30 points of damage.

In return the Death Knight casts Staggering Smite, and attacks 3 times (at advantage thanks to reckless attack) at like +11 vs the Barbarians likely terrible AC, likely hitting all three times.

The Barbarian halves the 3d8 + 15 weapon damage, but the 12d8 necrotic, and 4d6 psychic damage, isnt halved.

He takes 90 damage and probably drops to 0 HP by the end of round 1.

 

[Nitrosaur]

That is very similar to what I did in post #3, I think I will add the Command Undead if you don't mind. That is a nice thematic option.

Sure, no problem. And thanks!

One thing I did was just give it 2 legendary actions and its move action is only up to half its speed. It feels less like it is running all over the place that way. Since I lowered the number of attacks on its turn, it didn't actually change its CR.

Yeah, if I ever rework my DK I would probably lower the speed of the legendary action. Also, 2 legendary actions with one attack per LA is more elegant than Double Strike, being one of my first monsters meant I was trying to adhere to the standard 3 legendary actions.

 

[Flamestrike]

LAs should really be 1 thematic one, 1 movement one, and 1 attack one.

I support the LA's at post 2.

For a BBEG you'd likely bump CR by 2 to account for the LA's, increase HP accordingly, add in a Nightmare mount, and some undead mooks (Strength 16 Wights in half plate with greatswords perhaps).

 

[dave2008]

Yeah, if I ever rework my DK I would probably lower the speed of the legendary action. Also, 2 legendary actions with one attack per LA is more elegant than Double Strike, being one of my first monsters meant I was trying to adhere to the standard 3 legendary actions.

FYI, the 3 LA is not a requirement, but it is the most common. For example, Demogorgon in OotA only has 2 LA. There are other's too, but that is the first one that I can remember.

 

[dave2008]

LAs should really be 1 thematic one, 1 movement one, and 1 attack one.

I support the LA's at post 2.

For a BBEG you'd likely bump CR by 2 to account for the LA's, increase HP accordingly, add in a Nightmare mount, and some undead mooks (Strength 16 Wights in half plate with greatswords perhaps).

FYI, I don't know how the MM CR 17 was figured, but the one in post #3 with the LA is CR 17 per the DMG guidelines (well 17.5 really, which from my experience WotC would bump to 18 - but I don't ) . However, if I added Legendary Resistance, that would change the CR.

I am going to see what I can do to improve its defenses some and maybe bump it to CR 18 as right now it is leans heavily on offensive CR.

 

[akr71]

Thanks folks. Upon reading the advice I will likely drop the Legendary Resistances, or give it a max of 1 or 2 and the Legendary Actions and focus on some Lair Actions. This is all still in the prep stage for a sandbox campaign - its good to have some tricks up my sleeve in case the party doesn't head to this particular location until much later and I need to boost the BBEG. I do what this creature to be a commander of undead and be able to control many of them.

Here is what I was playing with - its all very vague & just ideas:
Lair Actions - On Initiative Count 20:
Summon Undead - the lair is in on or near an ancient cemetery or battlefield (of course it is) - 6 skeletons, or 2 ghouls, or 1 wight crawl from the ground and join the fray. I kinda like this as a Legendary Action and plays into the Marshal Undead ability.

Negative Energy Burst
The DK points to a spot it can see within 60 feet of it and a burst of negative energy in a 30' radius fills that zone until init 20 the following round. For the duration, healing magic does not work.

Cold of the Grave
A location within 60 feet of the DK is filled with deathly cold. All creatures within a 20 foot radius of that point take 1d6 cold damage and have their movement halved while in the area (Con Save)

I was also considering some sort of charm/dominate person ability as a LA.

 

[dave2008]

Thanks folks. Upon reading the advice I will likely drop the Legendary Resistances, or give it a max of 1 or 2 and the Legendary Actions and focus on some Lair Actions. This is all still in the prep stage for a sandbox campaign - its good to have some tricks up my sleeve in case the party doesn't head to this particular location until much later and I need to boost the BBEG. I do what this creature to be a commander of undead and be able to control many of them.

Here is what I was playing with - its all very vague & just ideas:
Lair Actions - On Initiative Count 20:
Summon Undead - the lair is in on or near an ancient cemetery or battlefield (of course it is) - 6 skeletons, or 2 ghouls, or 1 wight crawl from the ground and join the fray. I kinda like this as a Legendary Action and plays into the Marshal Undead ability.

Negative Energy Burst
The DK points to a spot it can see within 60 feet of it and a burst of negative energy in a 30' radius fills that zone until init 20 the following round. For the duration, healing magic does not work.

Cold of the Grave
A location within 60 feet of the DK is filled with deathly cold. All creatures within a 20 foot radius of that point take 1d6 cold damage and have their movement halved while in the area (Con Save)

I was also considering some sort of charm/dominate person ability as a LA.

I like those lair actions. No OP but thematic and tactical, just like lair actions should be IMO

 

[dave2008]

Problem with command undead is that the DK itself does 27 per swing and has a high accuracy.

I noticed that too, that is why I added the attack with advantage bit. I was think about adding necrotic damage to the attack too.