Large Monstrosity, Chaotic Evil
Armor Class 16 Natural Armour
Hit Points 189 (18d12 + 70)
Speed 40 ft., Climb 30 ft., Swim 30 ft.
STR
23 (+6)
DEX
13 (+1)
CON
19 (+4)
INT
19 (+4)
WIS
17 (+3)
CHA
20 (+5)
Saving Throws INT +8, CHA +9
Skills Perception +10, Stealth +5
Damage Resistances Acid, Fire, Lightning
Damage Immunities Poison
Condition Immunities Poisoned
Senses Blindsight 30ft, Darkvision 60ft, Passive Perception 13
Languages Abyssal, Elvish
Challenge 12 (8,400 XP)
Proficiency Bonus +4
Traits

Innate Spellcasting. The Arcane Adversary's innate spellcasting ability is Wisdom (spell save DC 16). It can innately cast the following spells, requiring no material components: 

At will: animal friendship 

3/day each: Darkness, entangle, fear, haste, suggestion, polymorph

1/day: divine word

Magic Resistance. The arcane adversary has advantage on saving throws against spells and other magical effects.

Reckless. At the start of its turn the arcane adversary can gain advantage on all melee weapon attacks rolls, it makes during that turn, but attack rolls against it have advantage until the start of its next turn.

Actions

Multi attackThe arcane adversary makes one claw attack and one bit

Claw. Melee Weapon Attack: +7 to hit, reach 5ft., one target. H i t 13 (2d6 + 6)

Bite. Melee Weapon Attack: +5 to hit, reach 5ft., one target. H i t 13 (3d6 + 6)

Description

This creature barely resembles a humanoid and reeks of burned flesh and rott, an amalgamation of claws, ears and hooves from various animal parts forged together in some unholy arcane abomination before you, sharp teeth showing from it's snarling and drooling maw

Holyyeda