Making Monsters Made Easy
Last week, we talked about making NPCs in Dungeons and Dragons Fifth Edition. Today we'll look into the more challenging task of creating a monster, or a combatant NPC from scratch. Generally, this is much harder because there is a lot more math involved and you might generally be worried that you will make some savage beast that will murder your whole party of players and you yourself will be seen as a monster. However, I've come up with a way that breaks down the monster creation into a series of questions that can very quickly dispel most of your fears. In the third section of the Dungeon Master's Guide a lot of this is covered with a number of charts and tables to quickly assess what your new monster's challenge rating will be. However, using some of that information, and our own logical approach to the math behind the game, this faster method of monster creation should help reduce your prep time, and make monster creation a little more fun.
(Sometimes I wish it worked like this. Art: Mimic Vat, Matt Covotta, Wizards of the Coast)
Initial Design
Let's call the type of character or monster we are making an Enemy. If we use this term, we already understand that this character or monster is being made with the ability to be fought in mind. Remember how last time, we said that we were only trying to make an NPC to do a task. We can start in one of two places, top-down or bottom-up. In a top-down design scheme, you start with an idea of what it will look like, be able to do, all within the fiction of the game. Say for instance, you say, "I want to create a monster that is like Godzilla." Godzilla is a gigantic, energy-beam shooting, bipedal reptile by definition. You then make mechanics that match that description, your creature has a well of hit points, gargantuan in size, a breath weapon, and is insanely strong, like a 30 in Strength. That very quickly defines mechanically how we would make Godzilla. On the other hand, bottom-up design would involve making the mechanics choices and then flavoring the monster to match the mechanics. For instance, your creation has the aggressive trait, grants other creatures extra damage, wields a greatsword, high Strength and Constitution, medium size: Let's make this an orc warlord and we're done!
I prefer top-down design personally, I design everything I make top-down because I am usually trying to meet a particular idea, whether it has been a request from a follower on Twitter, an idea for a cool item or class, or a general concept I want to bring to life. I'm always writing things from a top-down perspective. Some people might feel that bottom-up design is interesting, but again, in Dungeons and Dragons anything outside of what is in the books or a GM's game, there are no right answers.
Creation Q&A
In order to use this method of enemy creation we'll answer a series of questions, in the order it appears in a stat block like in the Monster Manual.
1.) What is name and type of creature you are creating, and what size is it? The only one of these factors that matter the most will be the size. The creature's size should be taken into consideration as you determine a creature's hit points, AC, reach, and ability scores. You generally won't see gargantuan creatures with high Dexterity scores, but will generally see high Strength scores and Constitution scores with such creatures.
2.) How hard to hit is this enemy? The math we should use will be made up of its Dexterity score, so hold onto that for later, but we'll come up with a base number. Decide whether it is natural or manufactured armor. If it is natural armor, it will generally have between a +1 to +3. Though as the DMG reminds us, monsters can have higher if their armoring is exceptional like gorgons who have a +9. Manufactured armor will follow the equipment chart and the general rules for items.
Keep in mind, that a level one character will have on average about a +5 to hit with an attack. For an enemy with an AC of 15, a level 1 character will hit it, on average fifty-five percent of the time (11 out of 20 possible faces of the die 10-20 yield a hit). The higher the AC, the less likely a character hits the enemy. This may seem obvious, but doing the math, a player character with the highest possible attack bonus by level 20 without magic items is a +11. Meaning, hitting an enemy with an AC of 15 reduces the number needed to rolling a 4 on a d20. That is a rate of only fifteen percent chance of failure. Keeping this sliding probability in mind will greatly help you find the middle ground you are looking for.
3.) How many hits can this enemy take? A monster's size generally determines its Hit Dice. Starting at Tiny- d4, Small- d6, Medium- d8, Large - d10, Huge - d12, Gargantuan- d20. Once you have the Hit Dice you need, equate it to a weapon. For most of these dice, we can compare it to a weapon type. Longswords deal d8's and d10's of damage. If the average ability modifier with a weapon will be around +3, you can easily piece together that one longsword hit will be 1d8 +3 damage. For your Medium and Huge creatures, how many longsword hits on average will kill this enemy? As long as its Constitution modifier is a +3 or lower, this question is easy. If it is greater than +3, that isn't a big problem, but we can assume the extra number of hits needed to kill it based on the average damage of a longsword (7.5).
For instance, a Mindflayer's Hit Dice is 13d8 + 13. That averages to be about 71.5 (or 71 according to the Monster Manual). If average longsword damage plus the modifier is 7.5. It takes roughly 10 hits to kill a Mindflayer with a longsword. If the Constitution modifier was +3, the answer would be that it required roughly thirteen hits- as many as it has Hit Dice! Asking yourself how many hits should kill this new enemy not only will help you establish its longevity in a fight but also the number of rounds in combat it will take to kill it. Assume for every player character each turn in the combat will be a potential hit (or more at higher levels). In a party of four, with each player having a single successful attack, the Mindflayer will die in roughly three turns. An 11th level fighter will hypothetically dispatch a Mindflayer three times as fast (three attacks around) as a level 4 fighter.
4.) How does it move and how fast? This is perhaps one of the easiest questions to answer. Keep in mind that if you give your monster a fly speed, that will limit the tactics your players can effectively use against it. There is no harm in doing so, but it keep it in mind as you are establishing hit points. Also, the faster a monster, the harder players have to work to move away from it. If retreating from it becomes less viable a tactic, you may want to consider lowering its damage output or you may accidentally create an inescapable killing machine. 5.) What are its ability scores? Using a scale of -5 to 10 what are its six ability scores? Don't worry about whether the creature should have a 14 or a 15 in Strength, just use the modifier directly. If it is bad at something give it a negative number. Apply whatever modifiers you need to the rest of the creature's stats and abilities.
6.) What is it's proficiency bonus? This is a pretty simple question as proficiency bonus only ranges from +2 to +6. The more powerful the creature, the higher its proficiency bonus should be. 7.) What are its skills and saving throws? If you want the enemy you are creating to have any skill or saving throw proficiency, you'll calculate it the same as you do for a player character. For creatures that should be really good at a skill, feel free to double their proficiency bonus for that skill.
8.) What special senses, defenses, or weaknesses does the creature have? Although this may seem a bit arbitrary, senses, resistances and weaknesses are good for really flavoring your creature as well as providing some interesting tactical opportunities. Perhaps if the creature is immune to being blinded, it already doesn't have eyes. That same creature you create could very well have blindsense. That creature will probably harder to sneak around. If that same creature is resistant or immune to a type of damage, that further differentiates the tactics used to destroy it. Vulnerabilities are much rarer for monsters but are a lot of fun for players to discover. This part isn't very math heavy, so don't fret too much, but make sure you don't go too overboard with immunities and resistances. There is already a Tarrasque.
9.) What are its actions in combat? Does it use natural weapons? Spell-like abilities? Spouts of fire. The main concern here is the action economy and the damage output. It is unlikely that a CR 1/4 creature will have more than one attack that deals a whole 2d6 damage on a hit. Actions can be daunting to create, but, use a similar thinking we used to determine the creature's hit points. What should one hit be capable of instantly killing? If your enemy for a group of level 1 characters could easily kill a level 3 barbarian in one hit, you've gone a bit far. However, is there the chance that it might kill a level 1 character in one hit, depending on how well it rolls? That is interesting, that adds tension. On average, you'd want that creature to be capable of dealing half an average character's health. So about 5 damage per hit in that case would be fine. If an action does less damage or have a saving throw, maybe it has an interesting effect like inflicting a condition on a character. Perhaps it moves characters around like Mortal Kombat's Scorpion or Overwatch's Roadhog. Don't be afraid to play around. The best thing you can do while creating this enemy is to ask yourself questions as you design. "If this too strong? How would it do in this situation?"
10.) Is there anything else? Perhaps it has Legendary actions, and Legendary Resistances. That's fine, but be aware how that changes the game. Maybe it has lair actions, or perhaps you want to try something brand new with this enemy. That's fine. Everything falls into one final rule: It is your game! You have an idea how your game works, what the players can do, and what is fitting for your game. Remember that it is just that, a game that you as a GM have control over. Don't be afraid to adjust things on the fly, or make adjustments after the debut of your creature. Your creature is your creation like the rest of the game. Don't forget to get your player's feedback on what you made. They might have feedback about it too. From there you can further refine your creature to make more appearances as a reoccurring villain or a new species of monster.
All else, have fun, Frankenstein!
Elsewhere in the Mage College
Sorry for the huge delay. My vacation ended with me being sick, with other things popping up immediately after. Starting 8/21/2017, I have something special planned.
Happy gaming, everybody!