Is there an appropriate place to specify class on a stat block?

Question

Every time I see a stat block for an NPC with a class (bard, druid, etc.), that class is not specified in the stat block. Is there anywhere where it could/should be specified when creating a stat block for an NPC villain?

Example: Ahmed Noke in A Wild Sheep Chase is a Wizard, but his stat block does not include this information.

I have a group of NPCs that are very similar to each other (same race, appearance, and name; they're clones of each other), but have different classes. I wanted to keep their stat blocks in the standard format, so that if other people wanted to use these characters, they can. I guess I just want them to look official, even though it's all homebrew.

Answer 1

Usually, only Player Characters have classes

While some monster stat blocks might have features that are analogous to a player class, they are not of that class. A monster's stat block should contain all the rules for that monster, and typically giving them full class levels would require more space than would be convenient. So, in official books, this simply isn't done.

For example, see the Mage (MM p.347). The Mage is a 9th-level spellcaster, as specified by their Spellcasting trait, and they have wizard spells prepared, but they are not a wizard. They do not have Arcane Recovery, for example, or any other class features of a wizard besides their Spellcasting trait.

Looking further, see the Spy (MM p.349). This is clearly based off a rogue, with a plethora of skills, Sneak Attack, and Cunning Action. But they have neither Thieves' Cant, nor proficiency in Thieves' tools. Despite borrowing traits from the rogue, the Spy is not a rogue.

You can add class levels to a monster, but...

Using the rules on Monsters with Classes from the DMG (p.283,) you can add class levels to any monster you'd like. The basic process for this is to simply add the class features from the class of your choice to the stat block. There is no need to add the class itself to the stat block; you've already added the relevant information (what the monster can do.)

To phrase all this another way: Player characters keep track of their classes because they change and grow, and must handle all kinds of metadata to make that happen smoothly. A normal monster does not change, so only the mechanically relevant information is listed on the stat block. Whether the monster is a bard isn't relevant; what bard features it has is relevant.

As of Boo's Astral Menagerie

Since this answer was written, there is now an official way to note class in the stat block. You can note it next to the creature type, such as:

Medium Humanoid (Gith, Warlock), Any Alignment

Be aware that, like this answer originally said, this does not imply that the monster has the abilities of that class. The only mechanical effect is to allow the creature to meet class prerequisites for the purposes of attuning to magic items.

Answer 2

Not officially, because monsters (inc NPCs) do not have player classes...

While there are stat blocks for humanoid creatures whose descriptions make it clear they are stand-ins for members of player classes, monsters do not use player rules or statistics, even when their attacks and abilities are clearly modelled after class features. Thus there is no official place to note class in a fifth edition stat block, and no existing rules that would make use of such information.

This is true even when making use of the DMG optional rules on adding class levels to a monster, as 1600hp points out in their answer.

...but the best place is probably as a tag

If you are home brewing something that makes this useful, and want to include it anyway, my suggestion would be to include it as a tag, which goes in parentheses after the creature type.