So I've been putting thoughts to paper, which generally can be a dangerous thing, and I expanded on the Monstrous Leaders thing I did years ago, to come up with something like this. Warning, it's fairly lengthy.
Leader Variants
Many groups of humanoids or other social creatures will have a single individual that leads them. These include but are not limited to alpha males/females, chieftain/chieftesses, captains, kings/queens, and cult/pack leaders. Many of these will have their own specific stat block entries as described under the monster entry. For those that aren’t specifically described, the following guideline can be applied:
Leader (5-10 members of a group)
+1 to each ability score, +1 CR, +2 HD, +1 damage to each attack, choose 3 minor lair actions
Lieutenant (10-25 members of a group)
+2 to each ability score, +2 CR, +1 Proficiency bonus, +5 HD, 1 extra attack action per round, 4 minor lair actions, one trait
Captain (25-50 members of a group)
+3 to each ability score, +3 CR, +1 Proficiency bonus, +1 AC, +7 HD, 1 extra attack action per round, 3 major lair actions, one trait
Chieftain/Chieftess (50+ members of a group)
+4 to each ability score, +4 CR, +2 Proficiency bonus, +2 AC, +10 HD, 1 extra attack per round, +2 damage to each attack, 4 major lair actions, two traits
Lair Actions
Clan leaders, chieftains or chieftesses, and other “bosses” will have the advantage when fighting on their home turf. They know the layout better than the PCs—where every crevice and nook is, they will typically have protections in place such as traps or cover, and they have minions to order around. They simply know where everything is in their lair, and can leverage that in combat.
How that looks in the game from a narrative perspective is up to you as the GM and depends on how the lair is actually described. Are there plates and utensils on a table nearby? Boxes or crates of supplies? Torches on sconces? Hidden rock fall traps or pits? The actual item may vary, but the effect as it is described below under the lair actions remains the same.
For those actions that force a saving throw or skill check, the DC = 10 + the creature’s proficiency bonus.
On initiative count 20 (losing initiative ties), the leader takes a lair action to cause one of the following effects:
Minor Lair Actions
- Utilizes an object within 10ft, such as a chair, tankard, rock, or other item to throw at one target within 30ft. If a ranged attack roll hits (Prof Bonus + Dexterity mod), then the target will suffer disadvantage on all attack rolls until the end of its next turn.
- Rallies an ally within 30ft with a motivational speech/bark/growl. That creature gains 1d6 temporary hit points.
- Grants a bonus reaction to any ally within 30ft, which is immediately used.
- Utilizes the terrain/furnishings that they are so familiar with to help avoid attacks, granting them a +1 AC bonus until the start of the next round.
- A pitfall, rock deadfall in the ceiling, or other trap is triggered in a 5ft square. Any creature within that area needs to make a Dexterity saving throw or suffer 6 (1d10) damage of a type based on trap (piercing for spikes, bludgeoning for rocks, etc.) and have their movement rate set to 0 until the end of their next turn.
- A light source (torch, fire, lantern) will flash in bright light. All creatures within 30ft of the light source will need to make a Dexterity saving throw or be blinded until the start of the next round. The creatures of this lair are immune as they are prepared for this and know what to expect.
- Roots or vines animate in a 5ft square. Any large sized or smaller creature in this area will need to make an athletics check or be grappled until the start of the next round. The creature may take their action to attempt to break free by making an athletics check.
- A fungi or flower expels spores in a 5ft radius. Any creature in the area of effect will need to make a Constitution saving throw or be charmed until the end of their next turn. Charmed creatures are in a stupor, considered restrained and unable to take any actions.
Major Lair Actions
- Choose any two minor lair actions to take effect
- A hidden passage opens, known only to the leader and the creatures of the lair. This is a hidden opening, requiring a perception check to succeed against a DC 10+leader’s proficiency bonus. This passage leads to another passage, to the surface, another room, or some other location determined by the GM.
- Vines and roots animate in a 10ft square. Any huge sized or smaller creature in this area will need to make an athletics check or be grappled until the start of the next round. The creature may take their action to attempt to break free by making an athletics check.
- Rallies an ally within 30ft with a motivational speech/bark/growl. That creature gains 1d8+proficiency bonus temporary hit points.
- Utilizes the terrain/furnishings that they are so familiar with to help avoid attacks, granting them a +3 AC bonus until the start of the next round.
- A pitfall, rock deadfall in the ceiling, or other trap is triggered in a 10ft square. Any creature within that area needs to make a Dexterity saving throw or suffer 17 (3d10) damage of a type based on trap (piercing for spikes, bludgeoning for rocks, etc.) and have their movement rate set to 0 until the end of their next turn.
- A fungi or flower expels spores in a 10ft radius. Any creature in the area of effect will need to make a Constitution saving throw or be charmed until the end of their next turn. Charmed creatures are in a stupor, considered restrained and unable to take any actions.
Traits
Many humanoid leaders will have additional traits beyond increased ability scores. These available traits are classified into four categories based on the general behavior of the leader: crafty, leadership, survival, and magical. For those traits that force a saving throw, the DC = 10 + creature’s proficiency bonus.
Crafty Traits
Alchemist: The alchemist carries 6 total pots, 3 of each type: damage and control. Damage pots are either fire or acid, chosen upon selection of this trait. Regardless of type, each pot explodes when thrown (50ft range) in a 5ft radius. Damage is 1d6 plus 2 points per prof bonus, Dexterity saving throw for half. Control pots are either grease or gas, chosen upon selection of this trait. Each pot has a range of 50ft, where it will shatter in a 10ft radius. For grease pots, a Dexterity saving throw is required or creatures in the area will fall prone. For gas pots, a Constitution saving throw is required for each creature or they will spend their next turn coughing, unable to take any actions.
Beastmaster: The beastmaster chooses a pet (wolves and giant rats are favorites among goblins, for example). This pet gains a bonus to HP equal to 2x final monster CR, and +1 bonuses to AC and attack rolls for every 2 final CR, minimum 1. For example, a CR 2 monster chooses this trait. The pet chosen by this monster gains 4 HP, and a +1 bonus to its AC and attack rolls.
Hunter: If the monster has a day to study an opponent (combat is not needed), it becomes familiar with the habits of that creature. That opponent will have disadvantage on all saving throws against the monster during the next encounter.
Stench: The monster has a horrible smell about it, caused by lack of bathing, covered in grime or feces, or both. Any creature entering for the first time, or starting their turn within 5ft of the monster must make a Constitution saving throw or suffer disadvantage on its attack rolls until the start of their next turn.
Trapper: A monster with this trait gains double its proficiency bonus when finding and disarming traps. Additionally, as a bonus action, the monster can remotely set off a placed trap up to a range of 50ft away. Reference the DMG for common trap types.
Leadership Traits
Battlefield Control: As a bonus action, the monster may move up to its movement rate in addition to any normal movement it may have used during its action. The monster may use this up to 1 time per 3 CR rounded down. I.e., a 7 CR creature with this trait can use this twice between short rests.
Bloodrage: As a bonus action, the monster can go into a bloodrage, increasing its damage by 2 points per CR for all attacks while in the rage. This ability will last for 1 minute, until the creature is incapacitated or brought o 0 or fewer hit points, or spends a bonus action to end it.
Go For the Throat: If an ally within 30ft of the monster successfully brings an enemy to 0 HP, the monster with this trait can issue a battle cry, allowing that ally to move up to its movement rate and perform another attack.
Inspiring Speech: By spending a bonus action to issue an inspiring speech, allies within 30ft gain advantage on saving throws until the end of the monster’s next turn.
Rally: The monster can spend a bonus action to rally allies within 30ft, gaining 1d8+CR in temp HP. This ability can be used once per encounter.
Warning: The monster spends a reaction to issue a warning to an ally within 60ft to impose disadvantage on the triggering attack against that ally.
Survival Traits
Begging: The monster has mastered the art of others feeling sorry for it. If reduced to ¼ or less of its maximum HP, the monster can take an action to beg. All opponents within a 30ft radius must make a Wisdom saving throw or feel sorry for the creature and not attack it until that creature performs another hostile action.
Dive (requires a fly speed): If flying and has at least 30ft to move, the monster can perform a dive attack with a melee weapon. If the weapon hits, an extra 1d6+1 per prof bonus damage will be inflicted. That is, a monster with a proficiency bonus of +3 can add an additional 1d6+3 points of damage to the melee attack.
Escape: The monster has chameleon properties, and can take a bonus action to attempt to hide. Cover is not needed, and this can be attempted in dim light.
Frenzy: If reduced to fewer than half of their maximum hit point total, the creature gains resistance to all piercing, slashing, and bludgeoning damage. The creature also gains a bonus +1 point per CR to each attack it makes, and advantage on any wisdom saving throws it may be forced to make during this time. This frenzy ends if the creature is brought above half of its maximum hit point total, it is incapacitated, reduced to 0 or fewer hit points, or there are no opponents within sight or hearing of it.