Figuring Out Combat in 5e: Making a Boss
This is the third part of a multipart series, the first part, Hitting Your Players, explores how you can hit your high AC/Level players, the second part, Monster Longevity, is how you can use the tools in the Monster Manual to help your monsters live longer. This post is going to focus on how you can turn a weak monster into a quick and dirty boss.
So your players have done it; despite your elaborate planning to kill them, the deadly traps you set and the cursed items you peppered throughout, they have finally arrived at the BBEG… The feared and all-powerful kobold leader simply known as… Meepo.
This is a battle to the death, the hardest battle they have ever fought and all you have to do is create your BBEG between now and the next session… except the party cheated. Either through a hole in the plot you forgot, a tricky spell like Wish, or just because you forgot to bring your fancy map you spent all last night drawing up; they are now way ahead of schedule and about to fight Meepo, the most scary and terrifying kobold ever to pull itself out of Kobold-dom.
You ask for a snack/restroom break and furiously begin workshopping a boss monster.
Hitting the Books
Starting out, we are going to review a specific section in the DMG, this will help inform our way on how to make a quick boss. If you aren’t interested in the how, I suggest jumping down to the next section, where we show off on what to do: Quick & Dirty.
On page 274 of the Dungeon Master’s Guide, there is a pretty handy chart on Monster Statistics by Challenge Rating. It breaks down Proficiency Bonus, Armor Class, Hit Points, Attack Bonus, Damage/Round, and Save DC per Challenge Rating of an average monster. This is a great chart for figuring out appropriate stats for your boss when you have the time to sit through and build a monster. We don’t have that time in this example, instead I think its an important chart to have a rough understanding of. You don’t need to know that a CR 10 creature has an average of 206-220 HP; though if you look at CR 10 creatures, most have less than 150 HP, let alone 200 HP. These charts can be weird.
Instead the important parts to know are:
Tier 1 Monsters (CR 1 - 4) have 50 - 100 HP and deal 15 - 35 damage per round
Tier 2 Monsters (CR 5 - 10) have 150 - 200 HP and deal 40 - 70 damage per round
Tier 3 Monsters (CR 11 - 16) have 250 - 300 HP and deal 70 - 100 damage per round
Tier 4 Monsters (CR 17+) have 350 - 500+ HP and deal 110 - 200+ damage per round
I don’t expect anyone to remember that, but it’s nice to have a general idea as to how strong a level appropriate monster should be. When you learn more about HOW things works, it makes it far easier to run the game. I suggest that a GM should read through Chapter 9 of the DMG, it has a lot of interesting rules and systems that you can add to your game to make it more than just a stock DnD game from a Hardcover adventure.
So, now that we know HOW things are supposed to look like, let’s go ahead and start creating our boss.
Quick & Dirty
Now that we have an understanding of how things are going to look, let’s go ahead and get a bit more information. Let’s assume that we have a level 15 party of 4 adventurers: Fighter, Rogue, Cleric & Wizard and that our boss will have minions about the battlefield. For our example, we will be basing Meepo the feared and all-powerful kobold off of the Kobold Monster stat block in the Monster Manual.
Whew! Those are some stats to be feared! Though sadly, our level 15 party is a bit stronger than the stock Kobold. But! This is only the basis for building our boss.
I suggest you get a note card when building your boss and follow along. I’ll be doing this for Meepo the Kobold Boss.
Before we can begin, you will need to find a weak monster for you to adjust the stats of. For selecting an appropriate monster to turn into a Boss, take your party’s Tier level and minus 1 from it. So a Tier 2 Party can have a boss stat block that originates in Tier 1 whereas a Tier 4 Party can have a boss stat block that originates in Tier 1 - 3.
Step 1 / Armor Class
Our first stat for Meepo is going to start at the top of the Stat Block, the AC of the monster. It’s important for Meepo to be able to avoid getting hit, but the players should still be able to hit them pretty regularly or they’ll stop having fun. This is a simple calculation of:
(Avg Character Level / 2) + 10 = AC
This gives Meepo an AC of 17, not anything to sneeze out and allows him to move about the battlefield pretty securely. You could, of course, just have different armor for different tiers:
Tier 1: Leather Armor (AC 11 + Dex Mod)
Tier 2: Ring Mail (AC 14)
Tier 3: Chain Mail (AC 16)
Tier 4: Plate (AC 18)
Using a set of armor for each tier helps take out some of the work for your boss and can help speed up this process. If the monster stat block you are working with already has a higher AC, just go with that.
Step 2 / Hit Points
The next change is going to be the hit points of Meepo the Potent. This is another simple formula:
Avg Character Level x d20 = Max HP
Based off what we did last week, we will have three numbers: Minimum, Average & Maximum HP. We just care about the maximum value for a Boss, so Meepo’s Hit Points will be:
15 x 20 = 300 HP
300 Hit Points is right on target per what we learned about Tier 3 Monsters having an average of 250 - 300 HP in the DMG. You can always adjust these if you know your players consistently deal large amounts of damage or deal small amounts of damage. Just add or drop 20 HP at a time to depending on how strong your players are. Its OK if you mess up the Boss’ health, you can adjust while they are fighting Meepo. That’s why you are there.
Step 3 / Ability Scores
We now have to look at the Ability Scores of Meepo the Invincible. This is a very tricky spot, if we increase these too much, than he will be unbalanced and may be too strong or too weak if we go in the opposite direction. My rule of thumb is to take the Tier of the Characters (Tier 3) and add that number to each Ability Score from the base stat block we are working from:
Strength: 7 + 3 = 10 (+0 Mod)
Dexterity: 15 + 3 = 18 (+4 Mod)
Constitution: 9 + 3 = 12 (+1 Mod)
Intelligence: 8 + 3 = 11 (+0 Mod)
Wisdom: 7 + 3 = 10 (+0 Mod)
Charisma: 8 + 3 = 11 (+0 Mod)
After adding in our +3 to those Ability Scores, you can immediately see that Meepo is Invincible for a reason… at least for a Kobold he is invincible. You can always massage these a bit more, but taking a weak monster and adding up to a +4 to each ability score can really help boost their power to be an appropriate challenge for your party.
Step 4 / Saving Throws
Now, our Kobold stat block doesn’t come with saving throws already. That’s OK! My rule of thumb is that a Boss has a number of Saving Throws equal to what tier your players are in. So that looks like:
Tier 1: 1 Saving Throw
Tier 2: 2 Saving Throws
Tier 3: 3 Saving Throws
Tier 4: 4 Saving Throws
The real kicker is… which ones do you pick? For Meepo the Strong, we have 3 saving throws to give him. Because Kobolds are naturally Dexterity based, I’ll choose Dexterity as his first one. The other ones can be more based off of the spells that your players use a lot or flavor. I typically pick Wisdom for my bosses to have a lot, though you can also choose Constitution, but that, combined with Wisdom & Dexterity, are the most used Saving Throws. I like to give my bosses one of the less used Saving Throws like Strength or Charisma for more flavor. Because Meepo is the leader of the Kobolds; he rules with fear and strength, so I’ll give him a Strength saving throw.
Meepo is now proficient in: Strength, Dexterity & Wisdom Saving Throws.
Now, to figure out the Saving Throw stat, we will take the Proficiency Bonus of the party characters (Level 15 has a +5) and add that bonus to Meepo’s stats.
Strength: +0 + 5 = +5 Str save
Dexterity: +4 + 5 = +9 Dex save
Wisdom: +0 + 5 = +5 Wis save
We are going to leave our BBEG skills alone. Those are more for flavoring and are up to you and your BBEG. If you do choose to give them a skill, just add the Proficiency Bonus of the party to that skill. Also, if your base stat block already has a Saving Throw they are proficient in, that counts against the number of Saving Throws your boss can have.
Step 5 / Abilities
Abilities of the Kobold are Sunlight Sensitivity and Pack Tactics. Now is the time to think about the flavor of your boss. By sticking with the stock Kobold abilities, he already is going to be doing pretty well when he has all of his minions milling about him. Depending on what Tier we are playing at, my monsters have different abilities that are always guaranteed to them. These are:
Tier 1: N/A
Tier 2: Legendary Resistance (1/Day)
Tier 3: Legendary Resistance (3/Day)
Tier 4: Magic Resistance, Legendary Resistance (3/Day)
Depending on your boss, it may make sense to give a Tier 2 or Tier 3 boss Magic Resistance as well, but that’s my general rule of thumb and what I would suggest as the minimum for a BBEG to have. We are going to give Meepo the Flawless access to the Tier 3 - Legendary Resistance (3/Day) so that Spellcasters aren’t just casting Hold Person and stopping him from doing anything all combat long. If they already have one of these abilities, just raise them up another tier.
Step 6 / Actions
Now comes how we are going to hurt our players, this will be pretty straightforward. We will give Meepo the Berserked multiattack, and he will get a number of attacks equal to the Tier of the characters. This is for martial characters, if they are a spellcaster than the number of attacks will translate to the number of dice they roll for their cantrips.
Tier 1: 1 Attack / Cantrip Die
Tier 2: 2 Attacks / Cantrip Die
Tier 3: 3 Attacks / Cantrip Die
Tier 4: 4 Attacks / Cantrip Die
Now, to figure out the To-Hit for Meepo the Stabber, it is his Dexterity Modifier (though most monsters use their Strength) plus the party’s proficiency bonus:
To-Hit: +4 + 5 = +9
The damage of each attack is going to be where we are going to have to do a bit more complexity. Right now, he is sitting at a 1d4 + 4 for his dagger damage. If he does that three times a turn, that only gives him an average of 20 damage per turn. Well, let’s go ahead and adjust what type of damage die he is using and we won’t be too worried about the specific type of weapon he is using. It’s ok to ignore the damage die that a weapon deals when it comes to making your monsters. You can flavor it as a dagger and still deal a d10 of damage. It’s all about balancing the amount of damage delivered per turn than what weapon they are using.
Tier 1: d6
Tier 2: d8
Tier 3: d10
Tier 4: d12
So going off of that, we can see that Meepo the Mighty will deal a d10 + 4 on his attacks. With 3 of those a round, he will deal an average of 30 damage on his turn. Which is still a bit low, even taking into account we will be giving him Legendary Actions in the next step. So how do we increase the damage of Meepo the Brave?
Well, this is a problem that many martial characters and monsters will face. Because of Meepo’s size, he doesn’t naturally get an extra damage die for it, but because he is a boss monster we can ignore that ruling. At Tier 2, bosses should be dealing an extra damage die when they take their attacks, and this bonus will increase for each tier. This bonus ignores the size of the creature in favor of balancing the encounter.
Tier 1: 1 Damage Die
Tier 2: 2 Damage Die
Tier 3: 3 Damage Die
Tier 4: 4 Damage Die
This gives Meepo 3 attacks, each at: 3d10 + 4 for an average damage of 21. In one turn, Meepo will deal ~60 points of damage to your heroes and will be truly the all-powerful entity that your party should be worried about.
Step 7 / Legendary Actions
Now, if you remember from the beginning of the article, a Tier 3 monster should be dealing between 70 - 100 points of damage a round. Meepo the Terrible is currently sitting around 60 points of damage on his turn, which is a bit low, but fear not - Meepo has access to Legendary Actions!
Every boss is not a boss until you give them the ability to attack at the end of another creature’s turn, and Meepo is no different. At the end of another creatures turn, 3 times, Meepo can take one attack. If Meepo makes all 6 attacks in a round; he is coming in at an average of 120 points of damage in a round. This is a little high compared to where a Tier 3 monster’s damage per round is at, but Meepo is a boss and is OK if he goes a bit over on the damage so long as you, the GM, are aware of how your players are doing. The goal is to not kill everyone, but give them a fight to remember.
Step 8 / Magic
One thing that we skipped over when creating Meepo the Magnificent, is spellcasting. This may take more than 5 minutes to put together, but so long as you have a fairly decent knowledge of what spells are good for combat you should do well. You can always look at what other monsters use for their spells, like the Lich or a Yugosloth.
To figure out how many spells a monster has, you need to figure out if your monster is a full caster, half caster or third caster. Full casters are your: Bards, Clerics, Druids, Sorcerers, and Wizards. Half Casters are Paladins and Ranger. Which leaves Third Casters as Eldritch Knights and Arcane Tricksters. By looking on page 165 of the PHB you can see the spell slot chart, or you can take half the level of the party, rounded up to figure out what is the maxed level spell slot that your BBEG has access too. I.e. If Meepo the Wizard could cast spells, the party is at 15th level, so he’d be able to cast 8th level spells.
The spell attack and DC is based off the casting ability of the monster (typically Wisdom or Intelligence) plus their proficiency, and if doing the Spell Save DC, plus an additional 8. So a monster with +3 Wisdom and +4 proficiency will have a +7 (3 + 4) Spell Attack Bonus and a 15 (8 + 3 + 4) Spell Save DC. From here, you need to pick their appropriate spells.
By giving your boss a lots of magic to perform, than take into account they probably aren't going to be a martial character and you should skip giving them mulitattack and increasing their damage. That, of course, is based on your table and your boss though.
This is a long article about building a quick boss for your games, and while that is a lot of words to read, going through the actual process is easy. By asking your party for a restroom/snack break, you can quickly grab your weak (Tier 1) monster stat block and adjust on a scrap piece of paper in 5 minutes. There is no need to end the game early if you follow these steps:
Find your base, weak monster (like a Kobold, Goblin, etc.):
Step 1: AC = (Avg Character Level / 2) + 10
Step 2: HP = Avg Character Level x 20
Step 3: Ability Scores = Tier Level + Stock Monster Ability Score
Step 4: # of Saving Throws = Tier Level
Step 5: Abilities = Add Tier Resistances (Legendary Resistance & Magic Resistance)
Step 6: Attack = # of Attacks / # of Damage Die / Type of Damage Die
Step 7: Legendary Actions
Step 8: Magic
To help you out, I’ve gone ahead and built a few more bosses from weak monsters - let me know what you think down in the comments!
Tier 2 Boss
Base Stat Block - Goblin
Level 9 Party
Tier 1 Boss
Base Stat Block - Sprite
Level 3 Party
Tier 4 Boss
Base Stat Block - Ogre
Level 20 Party
Tier 3 Boss
Base Stat Block - Cloud Giant
Level 13 Party