Use the approaches and examples in the following sections to build custom creatures for your game.
Baba Yaga invents a new creature—a fire-breathing giant toad!
You can change the superficial details of a creature’s appearance however you like, and you can alter any of the following pieces of a monster’s stat block without impacting its functionality.
You can alter a creature’s size and creature type as you please. For example, you can use an Ogre stat block for a human bully—just make it a Medium Humanoid instead of a Large Giant.
You can usually change a creature’s Intelligence, Wisdom, and Charisma scores freely unless the ability is used for spellcasting. For example, a Black Pudding stat block could represent a sapient alien if you raise its Intelligence and Charisma to 10 or so. It’s usually best to leave its Strength, Dexterity, and Constitution scores alone, as changes to these scores can alter a monster’s attack bonus, damage, Armor Class, or Hit Points, which in turn can alter its Challenge Rating.
You can change any or all of the languages the creature knows. You might want to add languages if you’ve made a creature sapient that wasn’t before. You can also add or remove telepathy or other forms of communication.
You can give a creature any skill proficiencies you want and give it Expertise if you want it to be very skilled. If you want a creature to be good at hiding, give it Expertise in the Stealth skill. If its keen senses make it an excellent tracker or otherwise adept at finding hidden foes, give it Expertise in the Perception skill. (You can also increase its Wisdom, as noted above.)
You can also swap a monster’s saving throw proficiencies. If it has none, you can add one or two.
Blindsight, Darkvision, Tremorsense, and Truesight have no bearing on a creature’s Challenge Rating. You can add or remove them freely.
If a stat block has spells, you can replace any of its spells with a different spell of the same level. Avoid replacing a spell that deals damage with one that doesn’t and vice versa.
You can freely change the name and flavor of an attack, as well as its damage type. For example, you can turn an ordinary Skeleton into an ice skeleton that deals Cold damage as it accosts characters with a blade of ice or hurls shards of ice at them.
If a creature doesn’t have Resistance or Immunity to one or more damage types, you can give it Resistance or Immunity to one or two damage types. You can also change the damage type of its existing Resistances and Immunities.
You can add traits to a creature’s stat block to communicate aspects of the creature’s nature. See the Creature Traits list for sample traits.
You can also use traits from other stat blocks in the Monster Manual, provided you don’t add traits that alter a creature’s Hit Points, confer Temporary Hit Points, or change the amount of damage the creature deals to other creatures.
Aversion to Fire. If the creature takes Fire damage, it has Disadvantage on attack rolls and ability checks until the end of its next turn.
Battle Ready. The creature has Advantage on Initiative rolls.
Beast Whisperer. The creature can communicate with Beasts as if they shared a common language.
Death Jinx. When the creature dies, one random creature within 10 feet of the dead creature is targeted by a Bane spell (save DC 13), which lasts for its full duration.
Dimensional Disruption. Disruptive energy extends from the creature in a 30-foot Emanation. Other creatures can’t teleport to or from a space in that area. Any attempt to do so is wasted.
Disciple of the Nine Hells. When the creature dies, its body disgorges a Hostile Imp in the same space.
Disintegration. When the creature dies, its body and nonmagical possessions turn to dust. Any magic items it possessed are left behind in its space.
Emissary of Juiblex. When the creature dies, its body disgorges a Hostile Ochre Jelly in the same space.
Fey Ancestry. The creature has Advantage on saving throws it makes to avoid or end the Charmed condition, and magic can’t put it to sleep.
Forbiddance. The creature can’t enter a residence without an invitation from one of its occupants.
Gloom Shroud. Imperceptible energy channeled from the Shadowfell extends from the creature in a 20-foot Emanation. Other creatures in that area have Disadvantage on Charisma checks and Charisma saving throws.
Light. The creature sheds Bright Light in a 10-foot radius and Dim Light for an additional 10 feet. As a Bonus Action, the creature can suppress this light or cause it to return. The light winks out if the creature dies.
Mimicry. The creature can mimic Beast sounds and Humanoid voices. A creature that hears the sounds can tell they are imitations with a successful DC 14 Wisdom (Insight) check.
Poison Tolerant. The creature has Advantage on saving throws it makes to avoid or end the Poisoned condition.
Resonant Connection. The creature has a supernatural connection to another creature or an object and knows the most direct route to it, provided the two are within 1 mile of each other.
Siege Monster. The creature deals double damage to objects and structures.
Slaad Host. When the creature dies, a Hostile Slaad Tadpole bursts from its innards in the same space.
Steadfast. The creature has Immunity to the Frightened condition while it can see an ally within 30 feet of itself.
Telepathic Bond. The creature is linked psychically to another creature. While both are on the same plane of existence, they can communicate telepathically with each other.
Telepathic Shroud. The creature is immune to any effect that would sense its emotions or read its thoughts, as well as to spells from the school of Divination. As a Bonus Action, the creature can suppress this trait or reactivate it.
Ventriloquism. Whenever the creature speaks, it can choose a point within 30 feet of itself; its voice emanates from that point.
Warrior’s Wrath. The creature has Advantage on melee attack rolls against any Bloodied creature.
Wild Talent. Choose one cantrip; the creature can cast that cantrip without spell components, using Intelligence, Wisdom, or Charisma as the spellcasting ability.