5e: CR31+ Monsters

A while back I posted a series of statblocks representing the avatars of gods and powerful fiends.

• The Red Knight, Goddess of Strategy
• Valkur, God of Naval Warfare
• Asmodeus, Lord of Hell (or, as in my world, the God of Sin)
• Pazuzu, Demon Lord

I specifically created these four as they are major players in my current campaign, but they were fun to make and you can probably expect me to return to the series with further entries some time in the future. (and if you've got a particular entity you'd like to see, feel free to reach out with a suggestion!)

Some of the statblocks I presented had CRs higher than 30. As part of my first article on the Red Knight, I briefly discussed how I had calculated these CRs. I thought that today I would return to this subject with a more in-depth explanation of the decisions I made to arrive at these CRs.

To follow along with the article, you will need to have access to the guidelines for Creating a Monster from the Dungeon Master's Guide (or an electronic equivalent such as D&D Beyond or Fantasy Grounds).

Asmodeus by Eric Deschamps

Making a CR 31+ Monster

When determining the CR of a monster, the guidelines boil down all its complexity to an aggregate of four things: its Hit Points, it Armour Class, its Damage Per Round, and its Attack Bonus. Optionally, a monster's Save DC may replace its Attack Bonus if it primarily uses saving throw effects, meaning that there are five data points that may be fed into the calculation, but only four are ever used at one time. As you will already know, other features are factored into the calculation as modifiers to one of those five statistics. But the rules for those adjustments are already in place, whch means we can focus our attention on these five things.

We'll do that by expanding the Monster Statistics by Challenge Rating table to also include CR 31 - CR 40, but first we need to figure out what each CR increase should actually mean so that we can populate the table. This table includes the aforementioned five statistics, as well as the expected Proficiency bonus. While Proficiency is not factored directly into the CR calculation, it is naturally an extremely important statistics, and a useful guide on what a monster's ability score bonuses must be to attain an appropriate Attack Bonus or Save DC.

• Proficiency Bonus: The maximum Proficiency Bonus in the original table caps out at +9. This is, of course, three higher than the maximum Proficiency Bonus attainable by player characters. Given that fifth edition's bounded accuracy places upper limits on player defenses, it seems reasonable that we should be cautious of granting bonuses even higher than this. As you'll see when you read a little further, we cap Attack Bonus and Save DC, which means we can also cap Proficiency Bonus at +9.
• Armour Class: The maximum AC in the original table is 19, which is reached at CR 17 and never improves—meaning it is the appropriate AC for just under half of all CRs in the table. My assumption here is that the designers want to be sure characters have a decent chance of hitting even the most powerful monsters. Chipping away at monolithic amounts of hit points still feels like progress, but missing entirely too often is simply not a fun experience. It seems prudent that AC 19 should remain the appropriate value at CR 31 and beyond. The monster creation rules do allow variations in AC and provide guidance on how that affects the final CR, so it is possible for the ACs of the monsters you design to creep higher, simply be careful not to set an AC so high that the only way to hit is to score a critical.
• Hit Points: From CR 20 onwards, the expected hit point range increases by 45 hit points each time. Our addition to the table can continue this trend.
• Attack Bonus: Attack bonus increases to +14 at CR 30, rather than plateauing much earlier as some other statistics have done. In theory that means we could increase it, but should we? +14 is already going to hit most characters more often than not. Is it necessary to keep reducing that margin, until the only possible way for the monster to miss anybody is to roll a 1? I would argue no. Just as we want a monster's AC to feel like an attainable target, for players to feel good about an encounter they need to know that it is possible for the enemy to miss them, however small that margin may be.
• Damage Per Round: As with hit points, the ranges in the Damage Per Round column increase an equivalent amount for each CR above 20. In this case: 18. The additional CRs we are adding can continue to do so.
• Save DC: Save Throw DCs increase to 23 at CR 30, and absolutely should not increase any further. Why? Because a typical proficient saving throw bonus is, at best, +11. Even with their best saves, level 20 characters already fail saving throws over half the time. With the four saves in which they are not proficient and only add their ability bonus, they'd be lucky to even be able to make the save on a roll of 20. Note that because Save DC and Attack Bonus are given equivalency in the CR calculation, capping Save DC at 23 is also further evidence that Attack Bonus should cap at +14.
• Experience: CR 30 creatures are worth 155,000 xp, which 20,000 xp more than CR 29 creatures. I have simply increased the award of CR 31+ creatures by 20,000 xp per level. Practically speaking, these numbers barely matter. Characters that face these creatures and successfully defeat them will already have reached the highest level, or be a few levels shy of 20. In the latter case, defeating a CR 31+ creature might facilitate a jump from CR 17/18 straight to CR 20. It would be well deserved.

With this analysis done, we have established the pattern of improvement for CRs beyond 30: namely, that the hit point ranges of monsters with these CRs should increase by 45 each time, the Damage Per Round by 18, and the Experience award for defeating them by 20,000.

Monster Statistics by Challenge Rating 

(CR 31+)

		Defensive		Offensive
CR	Prof. Bonus	Armour Class	Hit Points	Attack Bonus	Damage/Round	Save DC	XP
31	+9	19	851-895	+14	321-339	23	175,000
32	+9	19	896-940	+14	340-357	23	195,000
33	+9	19	941-985	+14	358-375	23	215,000
34	+9	19	985-1030	+14	376-393	23	235,000
35	+9	19	1031-1075	+14	394-411	23	255,000
36	+9	19	1075-1120	+14	412-429	23	275,000
37	+9	19	1121-1165	+14	430-447	23	295,000
38	+9	19	1166-1210	+14	448-465	23	315,000
39	+9	19	1211-1255	+14	466-483	23	335,000
40	+9	19	1256-1300	+14	484-501	23	355,000

CR 31+ Features

When we talk about monsters with CRs of 31 and above, we're talking about creatures with effectively godlike power. On the face of it, simply increasing the hit points and Damage Per Round of the monster a few steps might not seem like it would properly account for that level of power. In reality, however, the continued scaling of those two features might quickly take the monster beyond the means of your party to even deal with. Increasing Damage Per Round in particular makes the creature far too dangerous for your PCs to risk facing without significant preparation.

That said, a godlike monster should be more than just numerical padding. The features you create for such creatures should reflect their level of power. My deific avatars have access to a feature called Godly Magic, which lets them reproduce any spell of 5^th-level or lower at will, and spells of higher level a certain number of times per long rest. In effect, this puts a cap on the destructive potential of the god while still demonstrating a near-limitless reserve of power. Another feature, Godly Resilience, grants proficiency to all saving throws and protects them from magical sleep, polymorph, scrying, and life drain. Naturally, all such features affect the CR of a level 31+ monster. Compare features you create as best as you can to other examples in the monster creation guidelines. When in doubt, make your best guess and it probably won't matter too much—after all, CRs are a rough guide, especially as they increase, and in any case monsters with CRs beyond 30 are meant to next to impossible for level 20 PCs to fight.

CR 31+ Hit Dice

I recommend that all CR 31+ creatures have d20 Hit Dice, regardless of their physical size. At minimum these creatures are powerful demi-deities, and worthy of epic endurance. Besides, at these hit point levels using smaller hit dice is just too great a hassle.

Why Bother?

With their maximum level set at 20, player characters are already meant to have a tough time dealing with monsters with CRs beyond 23 or 24. Beyond those CRs, monsters are theoretically the equivalent of Raid Bosses from MMOs—normally unattainable challenges that can only be overcome with large numbers or careful preparation.

Godlike monsters beyond CR 30 should be treated the same. Realistically, player characters should not face them without adequate preparation, which could take the form of one or more quests to find items that will weaken the monster or be especially effective when used against them. You could reduce the monster's hit points in the final encounter for each such item that is collected (or destroyed). You could give the PCs magical weapons that deal lots of bonus damage against the monster. Maybe the PCs find riddles or other clues which let them know how to interact with objects in the final encounter space to impair the monster's statistics, slow them down, etc.

It could be argued that you don't need the full statblock if you expect the PCs to have solutions before they face the monster. But let's be honest, players are unpredictable. Your party might find a way to meet the monster too early. If they do, they should face the price of rushing to the encounter. If any of them are fortunate enough to survive, they'll know better what they're dealing with, and why they have to prepare.

You might also want the statblocks of several such entities in case they ever come into conflict with each other and you need to adjudicate what happens. In my campaign, the Red Knight and Valkur are on the opposing side of a brewing conflict to Asmodeus and Pazuzu. If my players' choices every draw the story in a direction where two or more of them ever directly face each other in conflict, I'll be prepared for that situation.