Lately, I’ve played in some high-level Dungeons & Dragons games with enough invisibility to make me study how the feature works in the game. Despite all my years playing D&D—or perhaps because of them, invisibility in fifth edition often defies my expectations. I can’t be alone, so I wrote a quick guide to invisibility. At the end, I pose a brain teaser where invisibility and Mind Blank meets True Seeing.

D&D presumes that creatures can perceive the location of invisible creatures

The Player’s Handbook explains that when a creature becomes invisible, “The creature’s location can be detected by any noise it makes or any tracks it leaves.” This seems obvious, but the game design presumes more. In a Sage Advice segment, D&D lead designer Jeremy Crawford suggests assuming that creatures can usually locate invisible creatures based on sound and other clues. Signs like footprints on damp stone, the squeak of floorboards, the stir of tapestries, the twang of a bow, or the snicker-snack of a sword could all expose an invisible creature. The specific clues seldom matter, but unless invisible creatures attempt to sneak, something reveals their general location.

When we dream of becoming invisible, we tend to imagine roaming undetected, but the game’s assumption better matches reality. Even with your eyes closed, you can usually track someone moving nearby.

To avoid revealing your presence while invisible, you need to be sneaky. Outside of combat, that means Dexterity (Stealth) checks. Inside combat, that means taking the Hide action.

The need for stealth to go undetected benefits game play in two ways:

• Invisibility helps characters, but they still need talent and skill to evade detection. Otherwise, invisibility would just make a better replacement for stealth.

• Invisible foes become a bit easier to locate, making battles against them less frustrating.

Ultimately, the dungeon master decides when or whether to adopt the premise that creatures generally know the location of invisible foes.

A DM can rule that noises or distractions allow invisible characters to go undetected without stealth. Jeremy Crawford gives the example of an invisible wizard who doesn’t bother to hide from orcs. “The DM might decide that because the barbarian is screaming in their face and the rogue lit the gunpowder barrels nearby on fire and they just exploded, the orcs are not even paying attention and they don’t know where she is.”

To escape detection, creatures must hide

If creatures notice the location of invisible creatures, how does invisibility help? Normally, to hide, you need to be out of plain sight. Invisibility enables hiding anywhere.

Hiding prevents people from hearing you or otherwise discerning your location. “If you’re dashing around, swinging your sword in combat, or yelling to your friends, you’re not hiding,” Jeremy says. “People can’t see you, but they can certainly hear you.”

When you take the Hide action, you make a Dexterity (Stealth) check in an attempt to hide. If your check exceeds the passive perception scores of those who might notice you, you become hidden from them. If something imposes disadvantage on a passive perception score, the score is at a -5 penalty.

Someone whose passive perception fails to notice a hidden creature can spend an action to actively perceive them. Then, the action allows a Wisdom (Perception) check to beat the Dexterity (Stealth) check and locate the hidden creature.

Once you have made your check, you can move without making another check or spending another action to hide. That stealth roll from your Hide action continues to apply. The design aims to avoid slowing the game with rerolls.

Obviously, talking and other activities can ruin hiding. Attacks reveal your location. “If you are hidden—both unseen and unheard—when you make an attack, you give away your location when the attack hits or misses.” This rule’s wording makes clear that even though the attack exposes you after it hits or misses, you get the advantage of attacking while hidden. The Invisibility spell uses less careful wording, but its effect still lasts until you hit or miss. Jeremy says that the spell “doesn’t predict what you’re about to do.”

Invisibility benefits attacking and defending

You can attack a hidden and invisible foe by trying to guess its location. “If the target isn’t in the location you targeted, you automatically miss, but the DM typically just says that the attack missed, not whether you guessed the target’s location correctly.”

Even though creatures typically discern the location of invisible creatures nearby, invisibility grants powerful advantages. “Attack rolls against the creature have disadvantage, and the creature’s attack rolls have advantage.”

Because advantage and disadvantage cancel, if two invisible creatures swing at each other, they attack as normal with neither advantage nor disadvantage. Invisible creatures rarely trade blows, but blinded creatures in, say, Darkness or a Fog Cloud often do, and the offsetting advantage and disadvantage leads to normal attack rolls.

Invisibility blocks many spells from targeting you

Invisibility’s strongest advantage stems out of all the spells from Acid Splash to True Polymorph that only target someone the caster can see. An invisible creature gains protection from all these spells. Plus an invisible spellcaster can’t be countered. Counterspell is cast as a reaction, “which you take when you see a creature within 60 feet of you casting a spell.”

This makes Greater Invisibility the strongest defense spell for casters.

Occasionally, going unseen hinders allies. For example, Spirit Guardians says, “When you cast this spell, you can designate any number of creatures you can see to be unaffected by it.” When clerics cast Spirit Guardians, they can’t exclude the party’s invisible members from the guardians’ harmful effects. Likewise, the evoker’s Sculpt Spell ability requires the caster to see allies to exclude them from a spell’s area, so the invisible rogue gets more chances to show off Evasion.

Invisibility versus True Seeing and Mind Blank

True Seeing is a divination spell that grants Truesight and its ability to see invisible. Mind Blank makes its target immune to divination spells. Can someone affected by True Seeing see an invisible creature affected by Mind Blank? You might argue that the divination spell only affects the person gaining Truesight, and that their new perception isn’t blinded by a creature’s immunity to divination. Or does Mind Blank somehow cloud anyone attempting a divination spell? Do you have your answer?

Jeremy Crawford says True Seeing fails to reveal an invisible creature affected by Mind Blank. But in your game, you are the dungeon master. Your answer remains correct.