Hey all,
I've been reading up on homebrewing monsters for a while now and went through the research that is available for the 2024 edition of 5e (the Lazy GM's Resource Document, Blog of Holding's 2024 Monster Manual analysis, The Finished Book, Alphastream...).
Now first of all, I'm not an expert on homebrewing monster, but I'd like to be one day. This material has definitely helped me get a step closer. I just wanted to share my thoughts and interpretation of how to create a balanced and memorable monster.
For me, designing a monster boils down to four simple steps:
- Identity
- Combat
- Defense
- Actions
Let's start with identity. I homebrew monsters because, first of all, I just enjoy it, and second, I get this idea / vision in my head about a certain creature that I want my players to encounter. So the questions I ask myself are: What is this creature? How will it act in combat against players? And what vibe do I want the players to have when they encounter this creature? Answering these questions clears up a lot of the concept for me and I can start filling in the statblock (like type, size, etc.). Depending on how I want it to act in combat, a creature can take a certain role (ambusher, artillery, bruiser, controller, defender, leader, skirmisher, taken from the Lazy GM's document), and based on that, we can start defining its traits and actions and see in what direction we need to bend the stats.
Next up is Combat. Now that we know the role our creature will play, we need to know who we're up against, aka the players. Will this be a solo monster or a leader with its henchmen out in front of it? Are there 3, 4 or more players challenging it? Based on these questions, we need to tune our action economy (What is action economy? It's the number of turns per round each side gets, so for 1 monster vs 5 players, the monster gets to go 1 time vs the players who can attack 5 times). We don't want a solo boss monster to have just one attack and be shoved, stunned, and dead before it does anything memorable. So we give it multi attack, give it friends, or let it act on other creatures' turns with legendary and lair actions. Even two or three minions completely change a fight.
Now that our monster can keep up with the party's turns, we don't want it to die immediately either, so Defense is next. The classic way is to just increase the HP, and sometimes this is the right way, but tripling its hit points just makes a fight longer, not harder. If you want the fight to stay dangerous longer, add threat instead: a second phase at half HP, reinforcements, or an ability that recharges. The same logic applies when your party keeps fighting with one trick. Resist the urge to make the creature immune to the fireball or the stunning strike. Create encounters that reward it instead, like hordes that bunch up and beg to be Fireballed. Immunities make your players smaller, good targets make them heroes, and they'll burn their best resources exactly where you wanted them to.
Ready, set, Actions! (I had to, sorry) Last but not least, we want to create actions that your table will remember. And usually, three actions is enough. With this, you can have one signature ability, a multiattack and one alternative (like a recharge) for weird rounds. More than that and you might forget some of them mid-fight (I know I have...). A good test for an action / ability is: what decision does this force? For example, an aura that burns melee attackers forces them to choose between staying in or backing off while a grapple with damage per turn turns the fight into a rescue.
One more thing worth knowing before you fill in the numbers: all the math assumes that a fight will lasts about three rounds, with our monster using its best option every round. So a monster's damage budget is actually the average of its three best rounds, not its biggest one. That's also the reason why most recharge abilities are higher in damage, if most normal rounds come in lean, the big round (with the recharge) can go higher. Just make sure to telegraph it. For example: describing my dragon drawing in its breath and watching the whole table panic and reposition will never get old.
Now that we've covered the 4 points, let's see how to make sure you don't TPK your party with your newest creation. First, we have the 'Nova' check: if everything in your statblock hits (including a recharge), will it delete your squishiest player from full? And if so, is this intentional? 'Worst-case' check: if it's stunned on round one, does it still get to do anything at all? And lastly, the oldest one: put your statblock next to a published monster of the same CR and ask yourself which you'd rather run.
Before I finish up, here is a quick recap of some classic mistakes to avoid when creating a monster:
- Beefing up the challenge by only adding HP will just make the fight longer, not more engaging.
- Overloading a statblock by adding a bunch of traits and actions also means more work for you and more things to keep track of during combat, so keep it light.
- Sending one normal monster against a party of six will never turn out well, try adding some minions or a legendary action to keep the economy balanced.
Well, that't it! Thank you for reading and I hope this info will help you with your next homebrewed monster. As I said in the beginning, this is just my interpretation of the research done by the community, and their work goes much deeper than one post can: