The most misleadingly named spell in the whole game, because it detects neither evil nor good.
Today we’re looking at a 1st level divination spell called Detect Evil and Good. Available to Clerics and Paladins, plus a few subclasses and anyone who can Magic Initiate their way in, this is a spell with a name that has started more arguments than almost any other, because it does not do the one thing its name promises. It will not tell you the shopkeeper is evil. It will not out the lying noble. It does not read alignment at all. What it actually does is sniff out six specific creature types and a couple of holy or unholy spots, and once you know that, it goes from disappointing to surprisingly useful.
Sitting at a range of self, a casting time of one action, and a concentration length of up to ten minutes, Detect Evil and Good sweeps a 30-foot bubble around you. Ten minutes is a long duration for a first-level spell, long enough to walk a spooky hallway, clear a few rooms, or hold it up through a tense conversation. There’s no saving throw and no attack roll, because it isn’t targeting anyone. It’s a radar dish, and you are the antenna.
The reason the name is such a trap is history, and we’ll get deep into that later, because for forty years this spell literally read the good and evil radiating off of people. Fifth edition kept the old name and quietly gutted the old function. So let’s take a look at the rules as written, and remember, you can always fight me in the comments if you read it different.
RAW
- Casting Time: 1 action
- Range: Self
- Components: V, S
- Duration: Concentration, up to 10 minutes
Here’s the 2014 text, straight from the Player’s Handbook, page 231:
“For the duration, you know if there is an aberration, celestial, elemental, fey, fiend, or undead within 30 feet of you, as well as where the creature is located. Similarly, you know if there is a place or object within 30 feet of you that has been magically consecrated or desecrated. The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.”
Let’s slow down, because every clause here is doing work that the name completely fails to advertise.
“You know if there is an aberration, celestial, elemental, fey, fiend, or undead within 30 feet of you, as well as where the creature is located.” Read that list again, because that list IS the spell. Six creature types. Not evil creatures, not good creatures, those six types. A mind flayer, a devil, a ghost, a pixie, a fire elemental, an angel. You learn that one is near and roughly where it is. You do not learn what it is. The spell does not whisper “aberration” in your ear, it just pings that something on the list is thirty feet out and gives you a location. So a friendly couatl, which is a celestial and about as good as a creature can be, lights up your detector exactly like a pit fiend does. The spell truly does not care about the moral part.
Here’s the flip side that matters just as much. A human bandit, an evil cult leader, a murderer, an orc warlord, a lich’s still-breathing human servant, none of them register at all. They’re humanoids. Humanoids are not on the list. The single most common evil thing your party fights, other people, is completely invisible to a spell named Detect Evil. That is the whole misunderstanding in one sentence.
“Similarly, you know if there is a place or object within 30 feet of you that has been magically consecrated or desecrated.” This is the second half nobody remembers. If someone cast Hallow on a shrine, or defiled an altar, or an object is carrying that kind of sanctified or profaned magic, you feel it. In practice this is your tripwire for the Hallow spell and holy or unholy ground. Useful in a dungeon full of cultist altars, mostly irrelevant in a tavern.
“The spell can penetrate most barriers, but it is blocked by 1 foot of stone, 1 inch of common metal, a thin sheet of lead, or 3 feet of wood or dirt.” This is the see-through-walls clause, and it’s better than people expect. Your radar reaches through a normal wooden door, a curtain, a body, most interior walls, and tells you the fiend is in the next room. What stops it is a solid foot of stone, an inch of metal, a lead lining, or a good yard of packed wood or earth. So a thin sheet of lead is the classic way a smart villain hides from you, which is a fun detail for a DM to drop.
There is no At Higher Levels line on this one. Detect Evil and Good does not scale. A first-level slot and a ninth-level slot cast the identical spell, same 30 feet, same six types, same ten minutes. It is what it is at every level.
Limits and Cheeses
A couple of things to know before you lean on it, and the deeper dive lives in the companion post.
First and biggest, it does not identify. You get “one of the six types is here, roughly there.” You do not get which type, you do not get how many, you do not get how strong. A tarrasque, an aberration, would ping the same one blip as a single quasit. So Detect Evil and Good tells you that you are not alone, not what you’re about to fight.
Second, disguises and shapechangers are the eternal argument. A succubus wearing a mundane disguise is still a fiend, so most tables agree the spell pings her. A fiend hiding under a spell like Disguise Self is a table call, and a devil polymorphed into something that is genuinely a different creature type may not ping at all. That’s a rules debate I get into hard in the uses post.
Third, concentration. Ten minutes is great, but it’s still concentration, so you can’t hold this and a control spell at the same time, and one hit can knock it off. As a scouting tool that’s usually fine. Mid-fight it competes with better options.
I’ll keep the limits short here, because the real uses, the clever cheeses, the questionable table arguments, and a few properly cursed ideas all live in the companion post. Go read the Detect Evil and Good uses post for that. This one is about what the spell is and the wild story of how it got this name.
The 2014 version versus the 2024 version
This is the comment I get every time a classic name comes up, so let’s settle it. Did Detect Evil and Good change in the 2024 Player’s Handbook?
Barely, and none of the changes touch what the spell is for. Same 1st level divination, same one action, same V and S, same 30-foot reach, same concentration up to ten minutes, same six creature types, still no upcast. If you know the 2014 spell, you know the 2024 spell. But there are three small edits worth naming, because someone in your comments will bring them up.
One, the range. The 2014 version lists the range as Self and then describes a 30-foot bubble in the text. The 2024 version, page 261, just cleans that up and lists the range as 30 feet outright. Same radius, tidier wording.
Two, the holy ground clause. In 2014 you sense a place or object that’s been “magically consecrated or desecrated.” In 2024 that becomes sensing “whether the Hallow spell is active there.” They pinned the vague old wording to the specific spell that actually does consecration and desecration now, which is Hallow. In play it’s the same idea, you feel sanctified or profaned ground, it’s just named more precisely.
Three, and this is the only real mechanical nibble, the barriers. The 2014 spell is blocked by three feet of wood or dirt. The 2024 spell is blocked by just one foot of wood or dirt, grouping it right in with stone. So the 2024 version sees a little less far through wooden walls and packed earth. Tiny nerf, and honestly one most tables will never notice, but it’s a real difference if you want to be precise. Everything else is the same spell it’s been.
History
Now the part I love, because this spell has one of the strangest arcs in the game. The name Detect Evil is about as old as D&D itself, and for most of that history it did exactly what the name says. Then fifth edition kept the name and threw out the meaning.
In original D&D, the 1974 booklets, Detect Evil was there on day one. As the magic-user spell it read “a spell to detect evil thought or intent in any creature or evilly enchanted object,” and it politely noted that poison, for example, is neither good nor evil. The cleric got a version too, at a longer range and duration. So from the very start, the spell’s whole job was to point at a person or an object and tell you it was evil. Exactly the thing the modern spell refuses to do.
The Basic sets kept that. Moldvay’s Basic book has it detecting evil intentions or evilly enchanted objects out to 120 feet, making them glow, and it hands the hard question straight to the DM, telling you to sort out what counts as evil at your table and reminding you that chaotic is not always evil. Even back then the designers knew “detect evil” was a philosophical can of worms.
Advanced Dungeons and Dragons first edition, the 1978 Player’s Handbook, formalized it. Now it’s a Divination that “discovers emanations of evil from any creature or object,” and it’s reversible, so the same spell flipped becomes Detect Good. This is the first version tied directly to the alignment system, and it detects along a one-inch-wide path in the direction the cleric is facing, using the holy symbol as a component. Notice the shape of the idea, one spell, two directions, evil and good, which is where our modern combined name eventually comes from.
Second edition, 1989, is where the designers first got nervous about the spell being too good. They added a now-famous restriction. A person’s alignment only radiates under unusual circumstances, roughly, they have to be strongly aligned, devoted to it, at least ninth level, and actively intent on an appropriately aligned act. In plain terms, second edition stopped your cleric from walking into a tavern and lighting up every petty crook in the room. The spell became about detecting evil enchantments and genuinely monstrous evil, not everyday human jerks. That instinct, that pointing a detector at people’s souls is a mess, is the seed of everything that happens later.
Third edition and 3.5 went the other way and leaned all the way in. They split the one reversible spell into a whole family, Detect Evil, Detect Good, Detect Law, and Detect Chaos, and deleted the old Know Alignment. Detect Evil became a 60-foot cone you concentrated on, and it fed you information in stages, round one you sense that evil is present, round two you learn how many auras and how strong the strongest is, round three you pin down the power and location of each. It even had a table of aura strengths by hit dice, and if a good character pointed it at something overwhelmingly evil and far above their level, they could get stunned for a round. This is peak alignment radar. It read the moral fabric of the room in detail. And here’s my favorite deep cut, the 3.5 barrier line, one foot of stone, one inch of common metal, a thin sheet of lead, or three feet of wood or dirt, is word for word the line fifth edition’s 2014 spell inherited. They kept the plumbing and swapped the entire engine.
Fourth edition did what fourth edition did to a lot of this stuff. It largely dropped alignment as a mechanical thing, so the detect-alignment spells basically vanished for that era.
And then fifth edition, 2014, made the move that confuses everyone to this day. The designers took the two old reversible halves, Detect Evil and Detect Good, and merged them into one spell with both names welded together, Detect Evil and Good. But at the exact same time, they threw out the part where it reads alignment. No more auras, no more sensing evil intent, no more lighting up the bad guy. Instead they pointed it at the six creature types that come from other planes or beyond death, aberration, celestial, elemental, fey, fiend, and undead, plus consecrated and desecrated ground. So the modern spell wears a fifty-year-old name advertising a function it deliberately does not have. The 2024 version, as we covered, left that design fully intact and just tidied the wording.
So that’s the arc, and it’s a genuinely funny one. Detect Evil spent decades as the spell that reads the good and evil in a person’s heart, got reined in when designers realized that was a headache, and finally in fifth edition kept the name purely out of tradition while becoming a completely different spell, a planar and undead radar that could not care less about anyone’s morality. The name is a fossil.
Opinion
Detect Evil and Good is a good spell wearing a bad name, and the name is the only real problem with it. Once your table internalizes that it means “detect aberrations, celestials, elementals, fey, fiends, undead, and holy ground,” it turns into a quietly excellent scouting and safety tool. Walking point in a haunted crypt? You’ll feel the undead through the wall. Suspicious the ambassador is a devil in a nice suit? If they haven’t specifically hidden their type, you’ll know. Worried a room is warded or defiled? The spell tells you. For a first-level slot and ten minutes of concentration, that’s a strong package for the right campaign.
Where it falls flat is the human-shaped villain, and that’s most villains. The murderer, the corrupt guard, the cult leader who is just a person, none of them ping, and new paladins learn this the hard way the first time they proudly Detect Evil at a lying noble and get absolutely nothing. So its value swings hard on your campaign. Fiend-heavy, undead-heavy, planar games, it’s fantastic. A gritty game of human politics and mundane crime, it’s close to dead weight. Know which game you’re in before you prepare it.
So I want to hear it. Has Detect Evil and Good ever saved your party by catching something through a wall, or is it a trap pick that let a villain walk right past it? And be honest, did you ever cast it expecting to out the bad guy and get a big fat nothing? Let me know in the comments below, go read the companion post for all the ways to actually squeeze value out of it, and until next time, roll high and stay ridiculous.
