How can my PCs discover an NPC's class if they are trying to hide it?

Question

I'm pretty new to DMing and I'm working on writing a campaign in which it's important to the plot that the characters not know at first that the BBEG is a multiclass wizard-warlock. Basically, this character is an Elf Prince who is widely known to be a modestly skilled wizard, but he's also secretly taken on a warlock patron and is the leader of a small rebel cult.

Other than dropping hints about his patron, are there mechanics that can allow my PCs to discover his class, similar to a detect magic spell or an Arcana check? I'd like to avoid relying on meta-knowledge like "oh, that's a warlock spell" as much as possible.

How can my PCs discover an NPC's class if they are trying to hide it?

Answer 1

Attempting to discover class is missing the point

Class is a metagame concept. Although it maps to the game world, there is no way for a PC to know it. Besides, that's not really what you are trying to ask.

Put class out of your mind completely, ask yourself "how can my PCs discover that this character has secretly taken on a warlock patron and is the leader of a small rebel cult?" This is a much easier question to answer, you can probably think of many ways that this could be discovered.

How can my PCs discover that this character has secretly taken on a warlock patron and is the leader of a small rebel cult?

• Observing the NPC communicating with their patron
• Finding some paraphernalia related to their patron (an amulet?)
• Finding something that just doesn't add up (a candlelit room filled with demonic sigils)
• Interrogating cultists ("we have friends in high places!")
• Finding something that links the NPC to the cult (all cultists are marked with a tattoo)
• Linking them to the cultists in some other way (in a conversation about the cultists, the NPC seems off)

Answer 2

Class is a game mechanic, not an identification ¹

As explained very well in this answer, there is no such thing within the game as a "class". It is just a tool to help players design their character, a set of rules by which the game is played, and a label for quickly describing concepts.

There can be no in-game tool to reveal such a thing. It would be like giving a player a "Ring of Dice Determination" which let's the character know that someone is using plastic dice, metal dice, or an electronic dice rolling app. Or a divination spell to know someone's Experience Points.

More to your point, saying that "the characters not know at first that the BBEG is a multiclass wizard-warlock" has no bearing. I may be a good cook, but I would never call myself a "multiclass developer/chef". The characters can figure out motives and backgrounds, but they can't grasp "class"

¹ Now it is possible that within any given campaign, certain classes must perform a specific action or set of actions. Such as, all Wizards need to go to designated schools to learn. Or Fighters go through gladiatorial training. It still doesn't tell anyone what "class" you are, only that you're trained a certain way.

Answer 3

NPCs don't follow the same rules as PCs. They don't necessarily have any class at all, just a collection of abilities. Look at the Archmage, for example:

Spellcasting. The archmage is an 18th-level spellcaster. Its spellcasting ability is Intelligence (spell save DC 17, +9 to hit with spell attacks). The archmage can cast disguise self and invisibility at will and has the following wizard spells prepared:

While it casts wizard spells, note that it is an "18th-level spellcaster", not an "18th-level wizard".

It has no other features of a level 18 wizard other than what is listed in its statblock.

Answer 4

The only thing that comes to mind for me is an ability that the Fighter subclass Battlemaster gets at 7th level. If you spend a minute interacting with someone outside of combat, you can learn whether you are superior to, inferior to, or the equal of the other creature in one of a number of stats. One of those stats is total level. It won’t outright say “hey this person is a Wizard 4 Warlock 12” but if your level 10 Battlemaster looks at what ought to be a “modest” wizard and learns that he is the wizard’s inferior in total class levels, it might raise eyebrows. The same feature can also determine current HP, which could also clue a lower-level party that the person they’re talking to is more than he appears.

Answer 5

To hide that he is a warlock from the players meta knowledge, do not describe his abilities with meta terms. When he casts an Eldritch Blast, don't say Eldritch Blast, but instead describe that he invokes some magic.

An Arcana check would then be a good tool for them to find out more about that magic ingame. But you already know that one.

From there you only need to give them hints and opportunities to clue them in that they are a Warlock. They could see him reading in a book which he then quickly hides, if they are interested they could try to get their hands on that book. They could see him in a Situation where he has to use his Warlockpowers, and could then use the Arcana check to see if they know something about the magic.

No other specific mechanic comes to mind, and as other answers have mentioned the players wont be able to find out that he is of the Warlock class (because that doesn't exist ingame). But they can find out that he is what people in your world refer to as a Warlock by observering his actions in your world, and comparing that to what people in your world generally refer to as a warlock.

In most worlds that would be stuff like: He reads forbidden grimoires, he sacrifices life to gain power, and so on. But in your world it could be whatever NPCs say it is: Maybe you notice Warlocks by a Marking they have somewhere on their body, maybe they sleep during the day, maybe they don't like Brocoli.

Answer 6

@MivaScott's answer is correct in terms of how the question is precisely phrased (can my PCs detect an NPC's class mechanically). However, if your intent is to allow your PCs to discover that this NPC is indebted to a patron and gets power from them, which I think is your real goal here, your players could take a look at this question on ways to detect alignment or use a spell like Divination or Commune to get answers about this NPC. However, I do think that in-game hints and sleuthing will probably be the most satisfying and reliable way to encourage discovery, as to take any of these actions your players would still need some reason to do so.

Answer 7

In addition to Craztjk's suggestion, the Mastermind Rogue is also able to compare their own class levels to another creature's:

Starting at 9th level, if you spend at least 1 minute observing or interacting with another creature outside combat, you can learn certain information about its capabilities compared to your own. The DM tells you if the creature is your equal, superior, or inferior in regard to two of the following characteristics of your choice:

• Intelligence score
• Wisdom score
• Charisma score
• Class levels (if any) At the DM’s option, you might also realize you know a piece of the creature’s history or one of its personality traits, if it has any.