Something that tends to come up in encounter and monster design discussions are questions about how to design boss monsters, and I wanted to share my experience on how this could be done. D&D 4th Edition already did most of the conceptual legwork when it came to designing boss monsters, and 5th Edition inherits most of them.
The critical thing is that while you can assume that a CR 1/4 monster is a fair challenge to a level 1 PC, and that you could stat up a boss by taking a CR 1/4 creature multiplying most of its relevant numbers by 4, the boss still has a few critical weaknesses:
1. It only acts once per round. If it rolls low on initiative, players can take all their turns before it and neutralize it as a threat before the fight even really starts.
2. Because it only acts once per round, it might only be able to attack once. If you concentrate all of its potential damage into a single attack, that makes it way too lethal. You can’t have a low-level boss rolling 4d6 without flattening Barbarians in one good hit.
3. At the same time, if the boss misses its one strong attack, then it does nothing while it gets beat on for another whole round before getting to try again.
4. Since you’re only dealing with a single target, it’s easier to “crowd-control” the situation. If a Monk stuns one Orc, that’s 25% of the DM’s available firepower. If a Monk stuns an Orc Boss, that’s the entire encounter right there.
To fix these issues, we need to, simply put: give boss monsters as many standard actions as the players, and they need to be able to use those additional actions on different initiative counts, and they need some way to be able to shrug off debilitating effects.
4th Edition did it by giving Action Points to Solo monsters, giving them Minor Actions that were as powerful as Standard At-Will powers, giving them high initiative bonuses, and giving them Triggered Actions. For the crowd-control issue, it basically boiled down to 4th Edition having a completely different philosophy when it came to what sort of status effects you could throw at the enemy. You couldn’t exactly teleport the boss into another demiplane and call it good.
5th Edition takes a similar approach. Take a Dragon encounter for example:
The Lair Action happens on a guaranteed initiative count of 20, meaning the Dragon will almost always get to do one thing ahead of the rest of the party. That’s Action 1
Player 1 acts. At the end of Player 1’s turn, the Dragon gets to use its Tail Attack Legendary Action. That’s Action 2
Player 2 acts. At the end of Player 2’s turn, the Dragon gets to use its Wing Attack Legendary Action. That’s Action 3
Player 3 acts.
Player 4 acts.
The Dragon takes its normal initiative count turn somewhere in this list. That’s Action 4
When the round cycles, the Lair Action happens again, and the Legendary Actions are refreshed
If any of the players tries to throw a save-or-die / save-or-suck effect against the Dragon, it has three “get out of jail free” cards.
Combined, the Lair Action, Legendary Action and Legendary Resistance mechanics guarantee that the boss is going to be able to give you a least 1 round of a good fight.
Thing is, they never tried using these mechanics for lower level monsters, but there isn’t anything that’s stopping us from doing something like, say:
Hogger
Medium humanoid (gnoll), Chaotic Evil
AC 15
HP 66
Legendary Resistance (3/Day). If Hogger fails a saving throw, it can choose to succeed instead.
Action: Pushing Smash. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: Hit: 5 (1d6 + 2) bludgeoning damage and the target must make a DC 12 Strength saving throw. On a failed save, the target is pushed up to 15 feet away from Hogger.
Legendary Actions: Hogger can take 3 legendary actions, choosing from the options below. Only one legendary action option can be used at a time and only at the end of another creature’s turn. Hogger regains spent legendary actions at the start of its turn.
Legendary Action: Intimidating Shout. Hogger lets out a powerful yell. Each creature within 30 feet of Hogger must make a DC 12 Wisdom saving throw. On a failed save, the target is frightened of Hogger until the end of its next turn.
Legendary Action: Spear Throw. Ranged attack. +4 to hit, range 20/60 ft., one target. Hit: 6 (1d8+2) piercing damage. Being within 5 feet of Hogger does not impose Disadvantage on the ranged attack roll to use this action.
Legendary Action: Mace. Melee Weapon Attack: +4 to hit, reach 5 ft., one creature. Hit: 5 (1d6 + 2) bludgeoning damage.
And you could have this serve as a boss monster for four level 2-3 characters. It hits all of the notes we’ve been talking about:
- It can take three Legendary Actions after the players take their turns, then its own regular turn for a fourth action.
- It has Legendary Resistance to prevent it from being instantly locked down.
- The damage dealt by any single attack isn’t going to result in oneshots.
- It has a ranged attack that it can use even while engaged by other players so the DM can choose to try and spread around the damage across the rest of the party, and the other Legendary Action deals 0 damage if the DM just wants to throw some chaos into the situation without dealing more damage.
- And if you were throwing in a Lair Action, you could do something like “on an initiative count of 15” for some sort of Cave In ability that deals 1d4-1d6 damage on a failed DEX save.
Song of the Blade 