Behir 5e: Stats, Swallow Math and Lightning Breath

A behir is a CR 11 Huge monstrosity with AC 17, 168 hit points, immunity to lightning and a climbing speed that lets it fight from walls and ceilings. It plays as a three-step machine: Constrict grabs one character, Swallow takes that character out of the fight, and Lightning Breath (66 damage, DC 16 Dexterity) punishes everyone who lined up to help. The 2024 version is much faster at that machine: Swallow becomes a bonus action, so a behir can grab and swallow a character on the same turn, and its breath line grows from 20 feet to 90 feet.

Table of Contents

• •Behir Stat Block (2014)
• •The Behir in the 2024 Rules
• •How the Behir Fights
• •Running a Behir Encounter
• •How Players Beat a Behir
• •Behir Encounter Ideas
• •Frequently Asked Questions

Behir Stat Block (2014)

This is the behir from SRD 5.1, matching the 2014 Monster Manual.

The 2014 behir's offense lives in two attacks. The bite (+10, reach 10 ft.) deals 22 piercing. Constrict (+10, reach 5 ft.) deals 17 bludgeoning plus 17 slashing, 34 in total, and leaves the target grappled (escape DC 16) and restrained. It holds only one creature this way: a Constrict hit while it is already constricting someone still deals the damage but doesn't grapple.

Swallow is a separate action, not part of Multiattack. It is a bite attack against a Medium or smaller creature the behir is already grappling. Because that creature is restrained, the bite has advantage.

Stealth +7 and a climb speed of 40 feet matter as much as the damage. A behir in a dark cave can hang above the entrance and drop into melee unnoticed: its average Stealth roll of 17 beats the passive Perception of most parties.

The Behir in the 2024 Rules

The 2024 behir (SRD 5.2.1) keeps the same AC, hit points, CR and breath damage, then rebuilds how it grabs and eats people.

Three changes reshape the fight:

• •Swallow costs a bonus action. Multiattack (Bite plus Constrict) and Swallow now fit in one turn. A 2024 behir that wins initiative can remove a character from the battle before that character acts.
• •Constrict targets Strength, Swallow targets Dexterity. Armor class stops protecting anyone from the grab. A wizard with a −1 Strength save fails DC 18 on anything but a 19 or 20. Once restrained, the target makes the Dexterity save against Swallow with disadvantage.
• •The breath reaches 90 feet. The 2014 breath was a 20-foot line, so it mostly hit the creature constricted next to it plus whoever came close to help. The 2024 line can catch the archer at the back of the room too.

How the Behir Fights

2014 turn order. Round one: Multiattack, biting one character and constricting another (or the same one). Against AC 18 a +10 attack hits on an 8 or higher, 65% of the time, so the expected damage is about 14 from the bite and 22 from Constrict, roughly 36 a round. Round two: use Swallow on the constricted character. The restrained target gives the bite advantage, about an 88% hit chance against AC 18. On a hit the character is swallowed and the grapple ends, which frees Constrict for a new victim next round.

2024 turn order. Round one: Bite the toughest-looking character (30 damage on a hit), Constrict the weakest-Strength character within 5 feet, then bonus-action Swallow. A target with a +2 Dexterity save needs a 16 to resist and rolls with disadvantage, so it succeeds only about 6% of the time. A rogue with a +7 Dexterity save does better, about 25%. From round two on, the behir bites and constricts a fresh target each turn.

Breath when the line is full. Lightning Breath recharges on a 5 or 6, a one-in-three chance each round. Save it for a turn when two or more characters line up, which happens naturally once the party crowds around to free a constricted friend. At 12d10, a failed save averages 66 damage, a success 33. A level 9 wizard with about 55 hit points drops on a failed save.

Inside the behir. A swallowed character is blinded, restrained, has total cover from everything outside, and takes 21 acid damage at the start of each behir turn. The behir can hold only one creature at a time. If the swallowed creature deals 30 or more damage to it in a single turn, the behir makes a DC 14 Constitution save at the end of that turn. With +4 Constitution it fails on a 9 or lower, 45% of the time, and coughs the creature up prone within 10 feet.

Use the walls. The behir climbs at 40 feet (2014) or 50 feet (2024). On a cliff face or a cavern wall it can strike from above, then climb out of reach of melee characters who have no climb speed. A behir that has swallowed someone and is below half health should climb away with its meal. That turns the fight into a chase with a clock: 21 acid damage per round.

Running a Behir Encounter

A behir is 7,200 XP. Under the 2024 SRD budgets for four characters:

Under the 2014 Dungeon Master's Guide guidelines (what our encounter calculator uses), a lone behir against four level 9 characters lands at Hard (6,400 Hard, 9,600 Deadly). Against four level 7 characters it passes the Deadly threshold.

Levels 8 to 10 are the sweet spot. Below that, a swallowed character often can't deal the 30 damage in one turn needed to force the Constitution save, and 21 acid a round kills them first. At level 11 and up a lone behir is a Low encounter, and four characters get four turns for each of its one, so add support (or a second threat) to keep it from being dogpiled.

How Players Beat a Behir

• •Don't stand next to the constricted character in a straight line. Approach from different angles so one Lightning Breath line can't cover two of you plus the victim. In 2024, keep the party off any single 90-foot line toward the behir.
• •Free the victim before Swallow. In 2014 the party has one round between Constrict and Swallow. The victim can spend its action on a DC 16 Athletics or Acrobatics check to escape. Pushing the victim out of the behir's 5-foot reach, for example with Thunderwave, ends the grapple, and so does incapacitating the behir. In 2024 there is often no window, so high Strength and Dexterity saves matter more than AC.
• •Fight from inside. A swallowed character can still attack. Thirty damage in one turn forces the Constitution save. Fighters with Action Surge and spellcasters with high-damage single-target spells are the best people to be swallowed, which is grim but true.
• •Target its mind. Intelligence 7 (−2) and Charisma 12 (+1) are its weak saves, and it has no save proficiencies. Banishment is a Charisma save and takes it out of the fight for as long as concentration holds. Hold Person does nothing; it isn't a Humanoid.
• •Don't use lightning. It is immune. Lightning Bolt and Call Lightning waste the turn. Cone of Cold and Fireball both work.
• •Light the ceiling. Darkvision 90 feet and a climb speed make it an ambusher. Faerie Fire or Daylight removes the advantage of attacking from unseen angles.

Behir Encounter Ideas

The tollgate gorge. A merchant road narrows into a canyon where caravans keep losing their lead wagon. A behir nests on the canyon wall 40 feet up and only takes the first cart. The 2024 breath runs the length of the narrow road, so a column of riders in single file is a perfect line.

The swallowed heir. The party arrives at a collapsed temple just as a behir swallows the noble's son they were sent to escort and starts climbing a shaft toward its nest. He has maybe two or three rounds of acid in him. The fight is a chase up a wall, and if he dies anyway, a Revivify cast within a minute is the reward for cutting the behir open fast.

Lightning against stone. A storm-blasted mountain pass has a behir that hunts during thunderstorms, immune to the lightning striking around it. Characters wearing metal and standing in water attract it. A stone giant clan that lives in the pass offers the party safe passage if they kill it.

Frequently Asked Questions

What CR is a behir in 5e?

A behir is CR 11 (7,200 XP) in both the 2014 and 2024 rules. It has AC 17 and 168 hit points in both editions.

How does a behir's Swallow work?

In 2014, Swallow is an action: one bite against a Medium or smaller creature it is grappling, and a hit swallows it. In 2024, Swallow is a bonus action that forces a DC 18 Dexterity save from a grappled Large or smaller creature. Either way, the swallowed creature is blinded, restrained and takes 21 acid damage at the start of each behir turn.

How much damage does a behir's breath do?

Lightning Breath deals 66 (12d10) lightning damage on a failed DC 16 Dexterity save and half on a success. It recharges on a 5 or 6. The line is 20 feet long in the 2014 stat block and 90 feet long in 2024.

Is a behir a dragon?

No. A behir is a Monstrosity in both editions, so effects that care about Dragons don't apply. It speaks Draconic, which is a hook for stories about it serving or hating dragons.

How do you escape from inside a behir?

Deal 30 or more damage to it in one turn from inside. It then makes a DC 14 Constitution save and regurgitates you, prone, on a failure. If the behir dies, you can crawl out of the corpse with 15 feet of movement.

Can a behir swallow a Large creature?

Only in the 2024 rules, where Swallow works on a Large or smaller creature. The 2014 behir can swallow only Medium or smaller creatures, though it can constrict a Large one.

Stat blocks: System Reference Document 5.1 (2014) and 5.2.1 (2024), Wizards of the Coast, CC-BY-4.0. Tactics, encounter math and ideas are Loreify's own.