Sources
CR
Type
Size
Alignment
Movement

Relentless Juggernaut

Large Fiend, Unaligned

Armor Class 17 (natural armor)
Hit Points 161 (14d10 + 84)
Speed 30 ft.
STR
22
+6
DEX
12
+1
CON
22
+6
INT
8
-1
WIS
15
+2
CHA
16
+3
Saving Throws DEX +5, WIS +6, CHA +7
Skills Perception +6, Survival +6
Condition Immunities Charmed, Exhaustion, Frightened
Senses darkvision 120 ft., passive Perception 16
Languages understands all languages but can't speak
Challenge 12 (8,400 XP)

Traits

Legendary Resistance (3/Day). If the juggernaut fails a saving throw, it can choose to succeed instead.

Regeneration. The juggernaut regains 20 hit points at the start of its turn. If the juggernaut takes radiant damage, this trait doesn't function at the start of its next turn. The juggernaut dies only if it starts its turn with 0 hit points and doesn't regenerate.

Unusual Nature. The juggernaut doesn't require air, food, drink, or sleep.

Actions

Multiattack. The juggernaut makes two attacks. It can replace one attack with Deadly Shaping if it is ready.

Executioner's Pick. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit:17 (2d10 + 6) piercing damage, and if the target is a creature, its speed is reduced by 10 feet until the start of the juggernaut's next turn.

Fist. Melee Weapon Attack: +10 to hit, reach 5 ft., one target. Hit:11 (1d10 + 6) bludgeoning damage, and if the target is a Large or smaller creature, it must succeed on a DC 18 Strength saving throw or be knocked prone.

Deadly Shaping (Recharge 5–6). The juggernaut magically shapes a feature of its surroundings into a deadly implement. A creature the juggernaut can see within 60 feet of it must make a DC 18 Dexterity saving throw. If the saving throw fails, the targeted creature is struck by one of the following (juggernaut's choice):

Flying Stone. The target takes 22 (5d8) bludgeoning damage and is incapacitated until the start of the juggernaut's next turn, and the implement vanishes.

Scything Shrapnel. The target takes 14 (4d6) slashing damage, and the implement vanishes. At the start of each of its turns, the target takes 10 (3d6) necrotic damage from the wound left by the shrapnel. The wound ends if the target regains any hit points or if a creature uses an action to stanch the wound, which requires a successful DC 15 Wisdom (Medicine) check.

Legendary Actions

Implacable Advance. The juggernaut moves up to its speed, ignoring difficult terrain. Any object in its path takes 55 (10d10) bludgeoning damage if it isn't being worn or carried.

Rapid Shaping (Costs 3 Actions). The juggernaut recharges Deadly Shaping and uses it.

Lore

Relentless juggernauts are massive brutes that thirst for carnage. Their presence twists the world around them, allowing them to create weapons with which they can slaughter prey. Sharp iron fences, crushing stalagmites and blades of glass all conveniently appear in order to aid a juggernaut's brutality. Every juggernaut considers a certain area its territory and visits destruction upon all trespassers.