With a new Monster Manual on its way, how much has each classic D&D monster actually changed? We're examining some of the key differences of each monster, with today's focus on the Arcanaloth.
The arcanaloth (a spellcasting yugoloth) has jumped ahead in the 2025 Monster Manual, with its entry now appearing in the "A" chapter instead of "Y" for yugoloth. One downside to spreading out the yugoloths is that there's no longer an explanation for what exactly a yugoloth is in the Monster Manual. Demons and devils are somewhat easy to explain, but yugoloths can be a bit more difficult and are tied more closely to D&D lore than their other fiendish counterparts. However, the arcanaloth did receive a notable visual upgrade, which a cooler set of duds and a nifty soul tome (which we'll discuss more in a bit.)
In terms of statistics, the arcanaloth's AC increases by 1 to 18, its HP is significantly higher (175 compared to 104), and its Initiative bonus is now a +5 instead of a +1. It also now has proficiency in Constitution saving throws instead of Charisma saving throws, although all of its underlying stats remain the same. Oddly, the Arcanaloth's Arcana skill modifier has been given a decrease (+9 instead of +13) along with its Deception and Insight bonuses (both are now +7 instead of +9). The arcanaloth also no longer has resistance against bludgeoning, piercing, and slashing damage from non-magical attacks. Its weapon attacks are also no longer classified as being magical, although that's likely because no longer has weapon attacks in its arsenal.
Like the aboleth, the arcanaloth's ability to be reborn on its home plane when killed is now built into its statblock. It also has a new soul tome trait, which gives him a soul tome with distinct stats and access to a unique banishing claw attack. When using the banishing claw attack, the arcanaloth can force its target to make a Charisma saving throw or be sucked into the soul tome. If the creature fails three additional saving throws while in the tome, they become permanently trapped inside the book until its destroyed. This is one of the few examples of a creature ability requiring BOTH a successful attack and a failed saving throw to activate.
In terms of other attacks, the arcanaloth's claw attack has been upgraded to a fiendish burst which deals much more damage. (31 necrotic damage versus 18 slashing/poison damage). The fiendish burst can be used as either a melee or ranged attack and can be used as part of a multiattack action that the arcanaloth didn't have before. Functionally, the arcanaloth can deal 93 points of damage on a turn instead of 18 damage, making it much more powerful.
Keep in mind that the 2014 arcanaloth was focused on spellcasting every turn and had a range of damaging spells meant to balance this out. Almost all of those damaging spells were removed from the 2025 version of the arcanaloth, although it can still teleport as a bonus action and cast counterspell as a reaction without any limits.
All in all, the arcanaloth is much easier to run and is less dependent on spellcasting to threaten foes. It also has a new unique mechanic that helps it stand out.
The full statblocks of both versions of the arcanaloth can be seen below:
2025 Monster Manual
2014 Monster Manual
