Calibrating Monster Difficulty

[MrStabby]

I was wanting to calibrate my sense of difficulty for encounters/monsters in my campaign. My habit is to just eyeball encounters - it seems more reliable than an explicit CR calculation (although I find players like to get a breakdown of the XP they earn). I do play with some optimising players though (not just characters but also tactics) so I think my sense of difficulty is a bit skewed.

I will be running a game for some new players soon (new to me, not new to 5th edition) and I thought it would be interesting to see if other people's assessment of difficulty matched my own.

The following template is going to be used for a few of the BBEG henchmen (although they won't always be encountered alone). I expect the Party to be about level 11 to 13 when they begin to encounter these guys, with a couple of magic items each. I am looking for something that might not be a fight to the death (they can fly off to hunt the party down later) but should be the climactic fight of the day for the party (4 players).

What CR would you rate it as?




Fallen Angel
Medium Celestial, Lawful Evil

Armour Class 17 (Natural Armour)
Hit Points 190 (20d8+80)
Speed 30ft., fly 90ft.,

Str: 18 (+4)
Dex: 16 (+3)
Con: 18 (+4)
Int:17 (+3)
Wis: 20 (+5)
Cha: 23 (+6)

Saving throws: Wis +9, Cha+10
Skills: Deception +11, Perception +10, Religion +8
Damage Resistances: Necrotic; bludgeoning, piercing and slashing from nonmagical weapons
Damage Immunities: Radiant
Condition immunities: charmed, exhaustion, frightened
Senses: darkvision 600ft., Turesight 60ft., passive perception 20
Languages: all, telepathy 120 ft.
Challenge: XX

Legendary Resistance (3/day). If the Fallen Angel Fails a saving throw it can chose to succeed instead

Spellcasting: the Fallen Angel spellcasting ability is Charisma (spell save DC 19). The fallen Angel need not perform the Verbal or Sommatic Components for their spells. The Fallen Angel has the following spells prepared:
1st level (4 slots): Hex, Illusory Script, compelled duel, bane
2nd level (3 slots): Misty Step, Spiritual Weapon, Zone of Truth, Silence
3rd level (3 Slots): Bestow Curse, Dispel Magic, Animate Dead, Elemental Weapon
4th level (3 Slots): Banishment, Greater Invisibility
5th level (2 Slots): Dominate Person, Dream

Magic Resistance. The Fallen Angel has advantage on saving throws against spells and magical effects

Actions
Multiattack. The fallen Angel makes two melee attacks

Glaive: Melee Weapon attack: +9 to hit, reach 10ft., one target. Hit: 9 slashing damage plus 18 radiant damage

Draw out shadows (3/per day): The fallen angel pulls together nearby shadows to create a shadow under the command of the Fallen Angel

Legendary Actions
The Fallen Angel can take 3 legendary Actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creatures turn. The fallen Angel regains spent legendary actions at the start of it's turn.

Attack. The fallen Angel makes a Melee weapon attack.
Recover a Spell slot (recharges on a 6). The Fallen Angel Recovers an expended spell slot
Desolate Wail (costs 3 actions). The fallen Angel screams, each hostile creature within 20ft. must make a DC19 wisdom save or have disadvantage on all attacks and saving throws until the end of their next turn
Wing Buffet. The Fallen angel Makes a Flying move of up to 30ft without provoking attacks of opportunity

[Tawmis]

There's a way to calculate CR in one of the books (Monster Manual, maybe? At work at don't have them with me)...

But just at a glance, that's some insane stats and powers (granted a fallen angel, and all)...

So... I'd say it'd be pretty damn high.

[MrStabby]

There's a way to calculate CR in one of the books (Monster Manual, maybe? At work at don't have them with me)...

But just at a glance, that's some insane stats and powers (granted a fallen angel, and all)...

So... I'd say it'd be pretty damn high.

Yeah, there is a CR calculator in the DMG - but it is terrible. Well overly simplistic anyway.

It is good for a bag of meat where HP, AC and to hit modifiers are all it really needs. It is less good for rating flying for example, to keep out of range of enemies and how the benefit of that scales according to the range and damage of it's attacks and spells. Interaction of complex abilities kind of needs a more human eye than the algorithmic process in the DMG.

[Decstarr]

I'd say it depends entirely on the party composition and their way of fighting/synergizing. I've seen my party struggle with supposedly "easy" encounters as well as dominating "deadly" ones.

Concerning your question: I'd say it would range from easy - deadly. Yeah, I know, this is not very helpful. Assuming an "ordinary" party composition around lvl 12 with no specific background information about the Fallen Angel's abilities, I'd say it probably is a deadly encounter. Anything that combines mind control shenanigans with the ability to succeed on saving throws is just incredibly strong. I can see people beating him with good use of counterspell and general lockdown + range attacks, though.

[MrStabby]

I'd say it depends entirely on the party composition and their way of fighting/synergizing. I've seen my party struggle with supposedly "easy" encounters as well as dominating "deadly" ones.

Concerning your question: I'd say it would range from easy - deadly. Yeah, I know, this is not very helpful. Assuming an "ordinary" party composition around lvl 12 with no specific background information about the Fallen Angel's abilities, I'd say it probably is a deadly encounter. Anything that combines mind control shenanigans with the ability to succeed on saving throws is just incredibly strong. I can see people beating him with good use of counterspell and general lockdown + range attacks, though.

I am building up a ringbinder of monsters i have used so there will potentially be some reuse but I am focusing on the level 11+ role and this one game at the moment. For the first fight the party will have some advantage - maybe being attacked in a defensible position or something. Kind of a warning shot.

If they don't learn from seeing them in action or track down some lore on these guys I would expect them to have a hard time.

I am pretty happy with a deadly encounter (not a TPK but one or more players at risk of needing to make death saves). They are supposed to be part of climactic battles. I certainly agree with everything you say about lockdown and ranged attacks. Counterspell seems a bit less useful given the angel is so mobile - but some powerful spells have limited range so it might force some different tactics.

So I based the monster on the Deva in terms of stats - with a bit of a boost (add +1 CR for that). The Deva is CR10 so it is likely to be substantially higher than this. The spells do add a lot of versatility and some of them will also boost combat damage, guess +2 CR for that.

Legendary resistances and actions probably raise the CR by about 3. Rough Eyeballing therefore gave me a CR of about 16.

In terms of the party - a level 12 party should be able to face a CR12 monster as a medium encounter. A roadblock that may need some resources but not a real threat to them. I would raise that by +2 for the magic items they will have and another +1 if they have done research/made use of their observations. So a CR15 creature shouldn't be a problem. If we say we want it a tough fight - add CR+2 to the encounter difficulty for a CR17 then I would expect to have a bit of budget left for some low level mooks to round out an encounter.