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Arx

Large · Fiend · CR 9 · Lawful Evil

Source. Tome of Beasts 1 (2023 Edition)

17 (natural armor)

171 (18d10 + 72)

Ability Scores

Core attributes and their modifiers.

STR

DEX

-1

CON

INT

WIS

CHA

-1

Overview

Category Monsters

Size Large

Type Fiend

Alignment Lawful Evil

XP 5000

Initiative Bonus -1

Movement

Walk 20 ft (6.1 m)

Fly 30 ft (9.1 m)

Swim 10 ft (3 m)

Climb 10 ft (3 m)

Crawl 10 ft (3 m)

Senses

Darkvision 90 ft (27.4 m)

Passive Perception 16

Saving Throws

Strength +9

Skills

Athletics +9 Perception +6

Languages

Abyssal, Infernal, telepathy 60.0 ft (18.3 m).

Resistances & Immunities

Damage Resistances

cold, fire, lightning, poison

Traits

Immutable Form

The arx is immune to any spell or effect that would alter its form.

Magic Resistance

The arx has advantage on saving throws against spells and other magical effects.

Spiky Hide

A creature that touches the arx or hits it with a melee attack while within 5 feet of it takes 4 (1d8) piercing damage. This trait also applies to the arx’s walls.

Actions

Claw

+9 to hit, reach 5 ft (1.5 m). Hit: 3d8+5 slashing damage.

Melee Weapon Attack: +9 to hit, reach 5 ft., one target. Hit: 18 (3d8 + 5) slashing damage.

Multiattack

The arx makes two Claw attacks and one Spear attack.

Spear

+9 to hit, reach 5 ft (1.5 m). Hit: 2d6+5 piercing damage.

Melee or Ranged Weapon Attack: +9 to hit, reach 5 ft. or range 20/60 ft., one target. Hit: 12 (2d6 + 5) piercing damage, or 14 (2d8 + 5) piercing damage if used with two hands to make a melee attack.

Wall Smash

If the arx has its wall set up (see Emplace Wall), it can briefly close the panels of the wall in on each other. Each creature other than the arx between the panels in a 10-foot cone from the corner where the panels meet must make a DC 16 Dexterity saving throw, taking 28 (8d6) bludgeoning damage on a failed save, or half as much damage on a successful one.

Bonus Actions

Emplace Wall

Recharge 3–6

The arx extends its hardened elytra and casts them into the ground, creating a wall. The wall is 3 inches thick and is composed of two 10-foot-by-10-foot panels. The panels must connect perpendicular to each other, forming a corner behind the arx. If the wall falls in a creature's space when the arx places it, the creature must make a DC 16 Dexterity saving throw. On a failure, the creature takes 10 (3d6) bludgeoning damage, and the arx determines to which side of the wall the creature is pushed. On a success, the creature takes half the damage and decides to which side of the wall it is pushed.

About Arx

Arx is a large fiend with a Challenge Rating of 9. It has a lawful evil alignment.

In combat, this creature maintains an Armor Class of 17 and possesses 171 hit points (derived from 18d10 + 72).

Arx has communication capabilities including Abyssal, Infernal, telepathy 60 ft.. This allows it to interact verbally with various creatures and characters.

GM Tips: Using Arx

2 tips available

When using Arx in your D&D 5e campaign, consider these tactical approaches:

Flight Control Strategy: Target flying creatures with spells like 'Hold Person', 'Web', or 'Grease' to ground them. Without flight restriction, they can escape melee range easily. Consider area denial spells below their flight altitude to force them into disadvantageous positions.
Telepathic Communication: This creature can communicate telepathically, making it excellent for coordination with allies. Silence spells won't stop its communication. Consider 'Mind Blank' or abilities that block telepathy.

Player Guide: Facing Arx

2 strategies available

When your party encounters this creature, keep these strategies in mind:

Counter Flight Advantage: This creature can fly! Use ranged attacks, reach weapons, or spells like 'Thunderwave' to push it away. Consider 'Gust of Wind' or 'Earthbind' to ground it. Melee characters need fly speed or flight magic to engage.
Telepathy Awareness: This creature communicates telepathically! It can coordinate with allies silently. Silence won't stop it. Use 'Mind Blank' or abilities that block telepathy. Be cautious of mental attacks.

Encounter Building Calculator

Standard Party Encounter (4-5 characters):

This creature is a medium encounter for a party of 4 characters of level 9.

Solo Encounter:

A single character of level 12 (up to level 20) can face this creature in a medium to hard encounter.

Experience Point Thresholds:

Medium: 9,000 XP
Hard: 13,500 XP
Deadly: 18,000 XP

Based on D&D 5e Dungeon Master's Guide encounter building guidelines. CR roughly equals party level for medium encounters.

Frequently Asked Questions

What is the challenge rating of Arx?: Arx has a Challenge Rating of 9, making it appropriate for parties of level 9.0.
What type of creature is Arx?: Arx is a Large Fiend, which affects how certain spells and abilities interact with it.
What languages does Arx speak?: Arx can communicate in Abyssal, Infernal, telepathy 60 ft..