5th edition Monster Creation System Revised and Streamlined

After using it again after not having looked at my monster system for a week and a half, I realized that I needed to pull it out of the analysis. And that some of the numbers could use a bit of tweeking. So here it is with all of the charts and most of the analysis removed:

Creating Monsters:

The first step is to come up with a monster idea and an approximate CR.

Benefits and Penalties: While I give a set of formulae to determine the standard statistics and abilities for creatures of a given CR, if everything fit the average, that would be a bunch of boring monsters. So instead we assign benefits and penalties. A benefit is something that helps a monster or an ability that is stronger than the average for that CR. A penalty is something that harms the monster or is weaker than the average for that CR. Each penalty balances out one benefit. There is space for a couple of benefits that aren’t countered by penalties in each monster, with higher level monsters getting more benefits or powers.

A Creature with a CR below 1 gets 1 free benefit. CR 1-2 Gets 2 Benefits, 3-4 get 4, 5-6 get 6 and so on.
In all cases, round up.

Armor Class
AC = 12.5 + .2* CR
Every 2 points above average is worth 1 Benefit. Every 2 points below average for a CR is worth 1 Penalty. More than 3 Benefits from AC is probably too much.


Hit Points
HP = 10.5*CR +9

Each mode of movement the creature is worth one point. If all of a creature’s movement modes are slower than 20′ per round, that is a penalty. Every 30 feet or fraction thereof higher than 30 feet that a movement type gets is also worth 1 point

A creature gets CR/2 free movement points. Anything beyond that costs benefits.


Ability Scores
A creature’s ability score bonuses should total to 1.75 *CR, so if a CR 1 Creature has a Strength of 16, they need a single stat of 8 or 9 to cancel out one point of bonus or they must pay a benefit.

Saving Throws
Most monsters don’t get saving throws at all. Having a saving throw is worth one benefit, as is every 2 points assigned to that saving throw.


A monster gets 3 + 1*CR skill points for free.
Lacking any skills is worth 1 Penalty. Every 3 extra skill points is worth on extra benefit.

Each thing a monster is Vulnerable to is worth a penalty.

Resistances and Immunities
Each resistance or immunity is worth 1 benefit. A creature with a lot of immunities should usually pay for them with penalties in other defensive abilities

Perception modes:
Normal No cost to have, 1 penalty for lacking.
Darkvision No cost to have, no penalty for lacking.
Blindsight Costs one benefit to have.
Truesight Costs one Benefit to have.

Melee to Hit Bonus
Hit Bonus = CR+2
Bonuses and Penalties are assigned for each 2 point shift from the average.

Melee damage is 4 + 4*CR
This is roughly 1d8+1d8 per level, but different dice expressions that have average damage similar to that work well too. This damage is split between multiple attacks if the monster gets them. Every 4 points over or under is worth a benefit or penalty.

If a creature has no melee attacks, calculate ranged attacks the same way you do melee attacks.

If a creature has melee attacks, ranged attacks are one benefit per 3 points of damage they deal and per 2 points of to hit bonus (so a 3d6 attack with +6 to hit is worth 6 benefits.) This is a good place to fudge a little.

Other benefits and Penalties
This is things like the ability to use a poison, or 5 spell levels of spell casting, or attacks that automatically gain advantage. If a benefit is particularly strong, make it worth 2 benefits. Don’t worry too much about relative power of abilities unless they are very strong or very weak.

Saving throws
If a special ability allows a saving throw, the DC is 10 +CR/4. Count it as a bonus or penalty for every 2 points over under this number.

This is things like situational disadvantages, weaknesses, and behaviors that harm the creature.

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