In the D&D 2024 Monster Manual, don't be tempted to make Aberrations just humans in monster suits

Before Dungeons & Dragons even talks about what monsters are considered Aberrations, D&D has to explain what it means to be an "aberration" in the first place. Fortunately, the D&D 2024 Monster Manual is up to the task. So, according to lead designer Jeremy Crawford:

• aberration (ab-uh-rey-shuhn) n.  1  Ick.

What D&D really means when it categorizes a creature as an Aberration (as opposed to a Dragon, or Undead, or Monstrosity) is either 1) it's a creature from the impossibly unknowable Far Realms, or 2) creatures that popped out of, or has been altered by, the Far Realm. Lots of mouths, eyeballs, and teeth. That's what I'm seeing.

Not all Aberrations are malevolent. Some are benevolent. Take for instance:

• Flumphs – But even they have an unknowable cheerfulness

But the majority are terrible, horrible, no good, very bad creatures, thank goodness. See:

• Aboleths
• Mind Flayers

Like other creatures that have shifted their categorization in the Monster Manual, some of these creatures are newly made Abberations. Such as:

• Githyanki – Militant theocracy, live in the Astral Sea; ride red dragons
  • New creature: Githyanki Dracomancer; leans into the relationship between Githyanki and Red Dragons (Challenge Rating 16, by the way)
• Githzerai – Fled to Limbo; entered a life of meditation
  • New types of Githzerai:
    • Monk
    • Xirth (spelling?)
    • Psion

They used to be Humanoid, but are now "way beyond Humanoid." They were transformed by the Mind Flayers to become a species with psionic powers, and that live in the Astral Sea (a place where time does not pass). They've been affected on such a fundamental level that there is something unnatural about them. 

Orcs are a species that have moved beyond their Humanoid origins and have become part of the NPC stat blocks. Orcs are no longer just a "monster" race. They've joined the ranks of species like Humans, Elves, and Dwarves. Just as you can find a variety of Humans, Elves, and Dwarves in the NPC stat blocks—from Acolytes to Veterans—that is also where you'll now find orc being represented.

Look around the 10-minute mark of the video. This is where Jeremy Crawford drops the bomb that the mysterious obelisks sprinkled throughout D&D 5e adventures (which have been given no official explanation up to this point) are revealed to be part of a master plan being executed by Mind Flayers. And by "master plan," Crawford explains that it's the equivalent of us looking up from Earth and seeing that Mars is about to crash into us.

Also, Mind Flayers don't think of themselves as people. They don't have personhood in the way humans understand it. If you've been going around saying, "Mind Flayers are people, too," you might want to check in with them on that. 

Designer F. Wesley Schneider reminds Dungeon Masters of a very important point. When it comes to figuring out the secrets owned by Mind Flayers and other Far Realm creatures, "Don't wait for us." Wizards of the Coast wants DMs to come up with these secrets on their own, make them their own, raise up or bury them on their own. Wizards has given us permission. We know what we have to do.

And Crawford would warn against turning every monster into just a human in a monster suit. That removes the specialness written into each and every one of these species. Besides, after 500 stat blocks to be found in the new Monster Manual, that trope would get boring. You're robbing your table of many different existential possibilities when you whitewash everything with a "humans are the real monsters" power washer. 

The D&D 2024 Monster Manual releases February 18, 2025. It will complete the trio of Core Rulebooks that include the 2024 Player's Handbook and 2024 Dungeon Master's Guide.