Monsters Spending Hit Dice for Special Effects Base Rules

Every creature has one or more Hit Dice. Characters possess as many Hit Dice as they have levels, whereas a monster’s stat block describes how many Hit Dice it has. For example, a 5th-level character has 5 Hit Dice, while a typical troll has 8 Hit Dice.

In the core rules, a character can expend one, some, or all their Hit Dice to heal hit points following a short rest. Players often overlook this rule or rarely use it, thanks to the ready availability of magical healing, which represents a missed opportunity. What if characters could put those neglected Hit Dice to work in some other way? TPK Games introduced the idea of spending Hit Dice for benefits beyond healing in their Recovery Dice Options book. So, in lieu of standard Hit Dice, a 5th level character would have 5 Recovery Dice to spend. Using the Recovery Dice rules, a character could choose from several thematic options when they spend Recovery Dice. Doing so would allow them to perform special attacks and maneuvers, albeit at the cost of no longer having those dice available for healing later.

Thanks to the Recovery Dice concept, player characters gained a host of new and fun options. But, what about the monsters? We’ve decided the time has come to level the battlefield. This book contains hundreds of options for monsters to spend their Recovery Dice, making the world a bit more dangerous and unpredictable for characters. By using this game mechanic, monsters can spend their Recovery Dice to perform special tricks and attacks, inflict additional damage, or accomplish exceptional feats with the traits and powers they already possess. One of the best parts about this is that the GM doesn’t need to change any monster’s stat block to take advantage of these options.

Each option in these rules lists its cost in Recovery Dice. In some cases, after the monster spends its dice, it simply rolls them and applies the total in some way. In many other cases, however, the monster spends the requisite number of dice to gain the benefit described.

Role-Based Options

Every monster has strengths and weaknesses. Some monsters, like giants, ogres, and trolls, dish out lots of melee damage and soak up damage themselves. Other monsters, such as wraiths and shadows, use their special abilities to attack from unexpected directions or sneak around enemy defenders.

The easy way to help the GM use a monster to the best of its abilities involves combat roles. A creature’s combat role quickly describes how a monster fights and how its special abilities can affect the battlefield or its enemies. For example, a Brute tends to have plenty of hit points, high Strength, and the ability to inflict lots of melee damage, while a Medic does what the name implies—heals and buffs its allies.

We’ve broken down combat roles into nine categories and provided examples of monsters appropriate for each. These roles aren’t prescriptive or exclusionary; it’s possible for a monster to fill more than one role depending on which of its traits it uses and how. Each role also provides a few appropriate Recovery Dice options. This offers a quick and easy way for the GM to use Recovery Dice without much preparation or bookkeeping. The GM decides what role a given monster plays in an encounter and allows it to spend its Recovery Dice on those options.

Combat Options

The Recovery Dice mechanic allows characters and monsters to trigger cool, fun, and entertaining options. Now, what if we take the concept a step further and weave this mechanic into how combat works? The GM and players can modify the existing combat rules with Recovery Dice in mind to make battles less predictable and more lethal or to give the campaign a grittier, more old-school feel. The following options allow you to adjust how healing, damage, and criticals interact with Recovery Dice.

Monstrous Options

Now we come to the meat of these rules. This section provides Recovery Dice options for a vast array of monsters listed in alphabetical order. Each monster entry includes one or more options designed to fit the creature’s theme, design, and abilities as described in the core rules. Thus, trolls don’t become immune to acid and fire damage, and a gelatinous cube doesn’t suddenly develop psionics by spending their dice.

Although these rules provides options for many different monsters, this doesn’t mean every monster in every combat needs or should use Recovery Dice. Allowing a monster to spend Recovery Dice makes them more noticeable, unusual, and individualized, which makes this option perfect for boss monsters and unique encounters. For example, if the characters encounter a dozen kobolds led by a shaman, it works best for the shaman to spend their dice but not the rank-and-file kobolds. The more monsters spending dice in an encounter, the more complex it becomes for the GM to run, and the more time it may take per turn. Then the GM wants to give a monster a few Recovery Dice options, they don’t need to make special preparations for the encounter. Once the encounter begins, the GM can open these rules, pick one of the chosen monster’s options, spend the Recovery Dice and watch the looks of surprised, shocked, and horrified players as they exclaim “that’s not in the rules!”

One of the other benefits of giving a monster Recovery Dice is how doing so can spark new ideas and possibilities in and out of combat. For example, check out the option Bringer of Nightmares, for the hag. Although this option can prove valuable in a fight, it also offers the GM some fun plot hooks and ideas outside of combat. The hag doesn’t necessarily have to use the knowledge it acquires right away; it could sell the information to the character’s enemies or hold it in reserve for future vengeance. Sure, there’s a time limit on the hag’s ability to frighten their target, but the knowledge itself remains valuable for a long time.

Using Recovery Dice

Total Party Kill Games first introduced Recovery Dice Options, a sourcebook of ways for player characters to use their Hit Dice (“Recovery Dice”) to do more than simply recover hit points as described in the core rules. This book offered dozens of options for many different classes, races, and campaign themes.

That about monsters? Do they gain Recovery Dice based on their Hit Dice? The core rules make no mention of monsters having the ability to spend Hit Dice to regain hit points. That being said, monsters—like characters—determine their hit points based on their Hit Dice. Whereas characters gain Hit Dice as they gain levels, monsters are based on their challenge rating. Since the system for spending their Hit Dice already exists and every creature has its own Hit Dice; we can easily graft this rule onto monsters.

Okay, perhaps we can give monsters the ability to expend Hit Dice, but should we? When it comes to monsters, let’s be honest: most never survive combat; the lifespan of a monster averages 24 seconds (i.e., four rounds) once they encounter the party. Thus, they have no need for long-term healing. In addition, with the exception of significant villains, most GMs never track monster hit points for those few that escape.

However, with so many new tools and tactics provided to characters in Recovery Dice options, it seems only fair that we return to the concept and level the playing field for monsters, villains, and other bad guys. Book of Monstrous Might returns to the idea and introduces dozens of ways for GMs to spice up their monsters and give adventurers new challenges to worry about. This book provides a range of ways for monsters to use this mechanic in combat. These options extend this game mechanic far beyond the realm of healing. Consider, for example, a dragon expending Hit Dice to recharge its breath weapon, a troll using them to accelerate its regeneration, or a fey creature using them to steal time from its enemies.

As indicated, the concepts and options included herein are just that—optional. We recommend you read through the possibilities before trying them in your campaign. Whichever options you choose, take things slow. Use a sprinkling of them to see how they affect the game. Be mindful that some of these Recovery Dice tools can alter the tone of your campaign by making combats grittier, more dangerous, more challenging, or lengthier. A monster’s use of a Recovery Dice option at the right moment can turn the tide of battle. These options make monsters tougher, more potent, and sometimes more complex to run. Thus, do not try to use every single idea included here. Instead, sprinkle them in to flavor your game like the master GM you are!

Recovery Dice Basics

The basic concept behind Recovery Dice remains the same for monsters as it does for characters. A monster can spend one or more Hit Dice, up to its maximum number of Hit Dice, a number based on the creature’s challenge rating. When it comes to healing, at the end of a short rest, for each Hit Die spent, the monster rolls the die (which is based on its size) and adds its Constitution modifier to it. The creature regains hit points equal to the total (minimum of 0). The monster can decide to spend an additional Hit Die after each roll.

Whether expending a Hit Die to activate an option requires an action or not is listed in the description.

Then a monster expends a Hit Die to activate an option, it does not regain hit points with that die unless the option chosen states otherwise. If a creature has no Hit Dice remaining, it cannot use any of these options. In some cases, expending a Hit Die involves rolling that die and adding the result to a game effect, such as an attack roll or ability check. In other cases, there’s no need to roll the die—the monster simply receives a benefit in exchange for expending one or more Hit Dice.

Since monsters rarely have the chance to gain a short rest or to heal, the options in these rules use Hit Dice to provide other benefits and enhancements. These options are grouped into categories based on monster types (e.g., aberration, fey, undead). Other categories are based on the monster’s role in combat, such as a leader or spoiler and include a brief description of what that role means in a fight along with suggestions for what monsters best fit that category.

Most of these options have no other prerequisites and can be assigned to any monster you choose. In some cases, however, a Hit Dice option only works if the monster possesses a certain power or special feature, such as the ability to cast spells, a breath weapon, or a bite attack.

If you want to assign a monster one or more Hit Dice options, you should do so ahead of time instead of once combat begins. Any option you give the monster should make sense for that monster and for the story.

Since these options can make a monster more challenging, and because they can make combat more complicated and time-consuming, you should limit their use to important monsters and encounters. Solo monsters, boss monsters, important NPCs, and major combatants represent the best candidates for having Hit Dice. Minions, minor henchmen, faceless hordes, and weak monsters should rarely use options for their Hit Dice.

Narrating The Dice

So what does it mean when a creature “spends” its Hit Dice? What resource do these dice simulate? on the base level, this pool of dice represents a creature’s ability to recover from injuries and heal wounds. Beyond this, Hit Dice can signify all manner of innate—but limited—resources: toughness, resiliency, determination, willpower, passion, innate magical power, or even supernatural power. Thus, a troll’s spending of its Hit Dice might reflect its physical recuperative abilities, while a vampire’s Hit Dice originate from the necromantic energy fueling its unlife. Thus, what a monster can do with its dice and how such an action appears often depend on the monster and the adventure scenario.

Then a monster expends Hit Dice, you should describe to the players what that action looks like or provide a hint as to what the monster is doing. While you don’t need to explain precisely what benefit the monster gains by expending Hit Dice, you owe it to your players to give them a bit of foreshadowing. In other words, describe the act of expending these dice into the adventure’s narrative.

For example, a red dragon expends a Hit Die to change its breath weapon to dramatically raise the temperature of the cavern instead of unleashing a gout of flame. When this happens, describe the heat ripples, the steam rising from every surface and the steady increase in the air temperature that makes breathing difficult and painful. Likewise, when a infamous orc warlord bellows out a war cry, and her eyes abruptly turn red; the players understand something dangerous has transpired, and their foe has become more dangerous, even if they don’t know the game mechanics of the change—they don’t know that her Strength has increased, and she’s gained temporary hit points. If you describe the use of Hit Dice in an interesting and dramatic way, you may well create new adventure hooks or future story ideas to add to the campaign.

Here are several suggestions and ideas for in-game descriptions of what occurs when a monster spends Hit Dice. Some of these suggestions don’t work as smoothly with some options, so let common sense and events in the encounter guide your descriptions.

• The monster utters a powerful battle cry that fills its allies with newfound courage.
• The creature invokes a dark power or calls for aid from its god.
• In spite of the creature’s mounting wounds and pain, it summons one final surge of desperate strength.
• A creature gives a stirring speech to its allies, invoking the legend of a great hero or leader.
• The monster asks the spirit of an ancestor to guide its actions and bring it success.
• The monster’s eyes glow or radiate some form of energy.
• The creature consumes a flask of some unknown alchemical brew.
• Thanks to exceptional intelligence and precise planning, the monster gains the exact advantage it needs at precisely the right moment.

Saving Throw DCs

Many Hit Dice options described below involve a target or other creature rolling a saving throw. Because these options were designed to work with a wide variety of different monsters, many of them do not include the specific saving throw DC. Instead, the options describe how to calculate the DC. Often, a save DC depends on the monster’s challenge rating; the higher the challenge rating, the higher the save DC.

In addition to including an ability modifier, a save DC may also include the monster’s proficiency bonus. As a quick and handy reference, the table below provides this bonus listed by challenge rating.

Challenge	Bonus
0 to 4	+2
5-8	+3
9-12	+4
13-16	+5
17-20	+6
21-24	+7
25-28	+8
29+	+9

If you want to modify the calculation used to determine a saving throw DC, you can increase it by adding the monster’s proficiency bonus (if not already included). Conversely, you can reduce the DC by leaving out the proficiency bonus. As a guideline, if an attack or effect is strongly associated with the monster’s core abilities or theme, go ahead and include its proficiency bonus. If, however, the attack or effect is more of a sideline or lesser power, go ahead and leave out the bonus.

Design Notes

Feel free to add your own Hit Dice options for monsters. When doing so, keep in mind a few things about which options can add to the fun and which might detract.

Be cautious about modifying a monster’s Armor Class. Even a small increase in a monster’s AC can cause a fight to bog down. As a guideline, character attacks should hit about 55 to 60% of the time; any change that dramatically reduces hit chances can lead to player frustration and slow combat to a crawl.

Modest increases to a monster’s hit points, whether by adding temporary hit points or healing damage, give a monster one more turn in which to act before it dies and usually don’t add too much to the length of a given combat. Be conservative, however, about using options that grant or recover hit points, especially with a monster that regenerates or has damage resistance.

For the most part, use caution with any option that adds the result of a Hit Die roll to another statistic. This is important because a monster’s Hit Dice are based on its size. This isn’t generally a problem for monsters that are Tiny, Small, Medium, or Large, since these Hit Dice are similar to those for the various character classes (ranging from d4 to d10). When it comes to a Huge or Gargantuan monster, however, a d12 or d20 die roll can add an extremely large number with a good roll and lead to rapid shifts in the flow of combat.

Not all the options provided in these rules work for every monster. Try to give the most appropriate Hit Dice options to a monster, i.e., those that fit with the monster’s size, appearance, type, tactics, and overall theme. Take, for example, the Thunderous Strike option. This feature presumes a somewhat strong, bulky monster with massive fists. While there’s nothing stopping you from giving this option to an orc, you should have some story-based reason for an orc to possess such an unusual ability.

If a monster uses a Recovery Die option that seems odd or out of place, you can bet your players will have questions. It’s fine to play against type, but you should have an in-game explanation for doing so. For example, it might not make sense for a wight or other undead creature to heal damage by expending Hit Dice. Instead, you could describe the undead creature picking up a chunk hacked from its body and sticking it back in place, or after the undead takes a bite out of an adventurer, it “heals” some of its wounds.

Regardless of how many Hit Dice a monster has, resist the temptation to feel you must use all of them in a battle. For a good guideline, limit the use of these options to three times in a battle. If you have a combat where two (or more) monsters have Hit Dice, limit each of them to no more than two uses apiece.

In most cases, there’s no need to alter the challenge rating of a monster or adjust the amount of experience awarded when a character defeats a monster using Hit Dice options. These options can make the creature a bit more dangerous or allow it to survive another round without any need to adjust the encounter difficulty. If, however, you find that the use of Hit Dice turn an otherwise average or easy encounter into a difficult or deadly one, feel free to award extra experience points equaling 10% of the XP value of the monster using this option. Of note, if your players are already using the concepts described in Recovery Dice Options, you probably do not need to adjust the encounter experience or difficulty level.

One final caveat worth mentioning again: do not try to use all the options contained in these rules! Some of these options contradict others or do not combine well, while a few different options achieve a similar effect but through different mechanics. Start slow and small, choosing a couple of options to see how they change your game and your adventures before digging too deep into the madness.

Lair Actions

A legendary creature often maintains a magical or supernatural connection to its lair as if the creature and its lair possess a symbiotic relationship. Through this connection, the creature can command its lair to attack or hinder intruders. Lair actions may manifest in the form of natural phenomena such as ceiling collapses, pools of water, or they may manifest as magical phenomenon such as unnatural darkness.

A creature’s lair actions reflect some aspect or theme central to that creature. For example, a green dragon holds a strong connection to forests. Its lair actions involve such things as grasping roots and vines and walls of thorny brush. A red dragon, on the other hand, has lair actions involving magma eruptions and blasts of volcanic gas.

Typically, a monster with lair actions can use one of them on initiative count 20 each round. Here are several options for how a legendary creature can combine Hit Dice expenditures with lair actions.

Batten Down The Hatches

The monster commands the doors within its lair to slam shut or swing open.

Effect: The monster spends its lair action and two Hit Dice to open or close any or all doors and windows within its lair. The monster can open some doors and close others in any combination. In addition, if the monster wishes, a closed door becomes affected by arcane lock.

Command Minion

The creatures serving the monster respond to its commands with urgency.

Effect: As a lair action, the monster can spend three Hit Dice to command all creatures of one type of minion. Those minions can then spend their reaction to move up to their speed. For example, the monster could use this ability to command all kobolds it can see or all ogres it can see.

Healing Power

The monster calls upon the ambient magic of its lair to heal its injuries.

Effect: As a lair action, the monster can spend one to three Hit Dice to regain that many hit points. The monster also adds its Constitution bonus to the amount of hit points rolled.

I Know You

The monster learns important information about an intruder, which is specific to the current encounter.

Effect: The monster can spend two Hit Dice and a lair action to learn the name, race, and alignment of one intruder it can see within its lair. The monster also learns why the intruder has entered the lair. The target creature can attempt a Wisdom saving throw (DC = 8 + monster’s Wisdom modifier + the monster’s proficiency bonus). If it succeeds, the monster learns nothing from this attempt to glean information.

I See You

With only a brief thought, the monster sees invisible creatures and objects.

Effect: When the monster uses its lair action and spends two Hit Dice, it gains the ability to see invisibility for 1 minute. Like the spell, this ability also allows the monster to also see ethereal creatures and objects.

Preternatural Senses

The monster’s connection to its lair grants it an exceptional sense it doesn’t normally possess.

Effect: The monster can use its lair action and expend two Hit Dice to gain one of the following special senses for 1 minute: blindsight 60 feet, darkvision 60 feet, tremorsense 30 feet, or truesight 30 feet. For three Hit Dice, the range of its chosen special sense doubles. If the creature already possesses a special sense and it expends two Hit Dice, it doubles the range it has with that sense to a maximum of 120 feet.

Spellcasting

The innate magic found throughout the lair aids the monster in casting its spells.

Prerequisite(s): Spellcasting ability.

Effect: The monster uses its lair action to cast one of its spells, up to 3rd level, without using any components or expending a spell slot. The monster must spend one Hit Die for each level of the spell cast. The monster cannot cast the same spell two rounds in a row. The monster cannot take other lair actions as long as it is concentrating on a spell cast as a lair action.

Tremors

A powerful tremor ripples through part of the lair.

Effect: The monster can spend its lair action and one Hit Die to cause the ground to rumble and shake in a 120-foot-radius around itself. Each creature other than the monster on the ground in the area must succeed on a Strength or Dexterity saving throw (target’s choice; DC = 8 + monster’s Wisdom modifier + monster’s proficiency bonus) or be knocked prone.

Tumbling Rubble

A section of wall or ceiling in the lair cracks and shatters, showering a pile of debris on intruders.

Effect: As a lair action and by spending two Hit Dice, the monster causes a pile of rubble or other debris to rain down on a 20-foot by 20-foot square it can see within 120 feet. A creature in the area of effect must succeed on a Dexterity saving throw (DC = 8 + monster’s Wisdom modifier + the monster’s proficiency bonus) or suffer 10 (3d6) bludgeoning damage and be knocked prone. The area of effect becomes difficult terrain.

Undisputed

While ensconced within its lair, this monster reigns supreme.

Prerequisite(s): The creature must have a lair and be able to take lair actions in order to use this option.

Benefit(s): While fighting within its lair, the creature can spend a Hit Die to reuse one of its lair actions, even if it hasn’t used a different one first. Alternatively, if it expends two Hit Dice, it instead increases the saving throw DC of a lair action by 2.

Regional Effects

Over time, the presence of a legendary creature can change, warp, or corrupt the land and the environment surrounding the lair. These effects, otherwise known as regional effects, fade or end if the legendary creature dies or abandons its lair.

Unlike legendary actions and lair actions, regional effects normally exist without the monster needing to do anything. Regional effects exist without the need for the monster to spend actions or expend Hit Dice. The new regional effects described below, however, are unusual in that they only take effect if the legendary creature spends the requisite number of Hit Dice each day. Thus, at the start of each day (such as following a long rest), the monster expends the number of Hit Dice required to create the regional effect—which in turn means the monster doesn’t have use of those Hit Dice for other purposes. Creating these regional effects doesn’t require an action.

Because regional effects connect to a legendary monster’s theme or concept, not all the options described below make sense for a given monster. A monster with no interest in beasts, for example, probably wouldn’t use the Beast Spy option.

Beast Spy

A mundane animal becomes a spy for the monster.

Effect: Once per day, the monster can spend one Hit Die to form a telepathic link with one beast friendly to it or charmed by it. This link allows the monster to send simple telepathic commands to the beast. The link also allows the beast to telepathically send basic emotions and simple concepts back to its master. This telepathy has a maximum range of 1 mile. The beast must have an Intelligence of 3 or less to be affected by this ability. The legendary creature can have multiple beast spies, but it must spend a Hit Die on each to form the telepathic link.

Dream Intrusion

The monster can invade the dreams of intruders within its domain.

Effect: The monster can spend three Hit Dice each day to create a programmed dream or nightmare that afflicts all sleeping intruders within 1 mile of the monster’s lair. This nightmare functions similar to a dream. The monster treats any intruder in the region as a creature it knows for purposes of this effect. The monster decides the nature of the dream and any message delivered to all dreamers. This effect cannot contact or affect creatures that do not dream, such as elves.

Enchanted Sleep

Intruders entering the region find themselves lulled into a deep, troubled slumber.

Effect: Each day the monster spends three Hit Dice, it places a magical curse upon the region within 1 mile of its lair. Any intruder entering this region must succeed at a Wisdom saving throw (DC = 8 + the monster’s Charisma modifier + the monster’s proficiency bonus) or fall into a deep, troubled sleep. An affected creature falls unconscious for 1d8 hours. Another creature can spend an action to awaken a creature affected by this sleep. Undead and creatures immune to being charmed are not affected by this power. Once a creature has been affected by this power, it becomes immune to the effect for the next 24 hours.

Plane of Origin

The monster treats its lair as part of its native dimension.

Effect: By spending two Hit Dice once per day, the monster treats its lair as part of its native plane. This means the monster is considered native to the plane upon which it dwells, such as for purposes of the banishment spell. If the monster spends one additional Hit Die, it gains further protection from banishment. If it fails its Charisma saving throw against this spell, it only remains trapped on the harmless demiplane for 1d4 rounds (rather than 1 minute), after which it reappears in the space it left or in the nearest unoccupied space if that space is occupied.

Speak Not The Name

The monster knows when its name is spoken within its domain.

Effect: A creature’s name holds power, and the name of a legendary creature holds tremendous power. If the monster expends two Hit Dice at the start of each day, it automatically knows when a creature within 1 mile of the lair speaks its name. The monster learns the speaker’s approximate location.

Spiteful Ruin

Throughout the region surrounding the monster’s lair, the water and food become tainted.

Effect: Each day, when the monster spends three Hit Dice, all natural water sources, all edible plants, and all creatures within 1 mile of the lair become toxic when intruders consume them. A creature that consumes anything toxic must succeed on a Constitution saving throw (DC = 8 + the monster’s Constitution modifier + the monster’s proficiency bonus) or become poisoned for 8 hours. A poisoned creature can attempt this save again at the end of each hour, ending the effect on itself with a success.

Halls Have Eyes and Ears

The monster can spy upon any creature within its demesne.

Effect: As a lair action and by spending two Hit Dice, the monster can cast clairvoyance anywhere within its lair with no need for components. The monster must spend its lair action each round to maintain concentration on this effect.

Thief’s Lament

The monster instinctively knows when a creature enters its lair.

Effect: Each day, the creature can place an alarm by spending one Hit Die for each entrance into its lair. This effect lasts until the next day. Like the spell, the monster can choose whether the alarm produces an audible or a silent mental alarm. The entrance cannot be larger than a 20-foot cube. an alarm triggers if a Tiny or larger creature passes through the entrance.