I'm building a character who is a Warlock. His patron is a great old one, which does not (initially) communicate directly. Instead, it gives the character urges and dreams, prompting him towards a certain path. It also allows the Warlock to understand some of the ancient tome the character bought, thereby giving him abilities that are associated with the Warlock class.

For the backstory I have in mind, the character would go through his initial steps as a warlock (e.g. learning some cantrips as nothing more than 'fancy party tricks') without knowing he has a contract/bond with a great old one. When the adventure starts (level 1), the character might already be aware of the fact he draws his power from his patron. This could depend on if the DM wants to incorporate it in the story or not.

Would this character have to be aware from the start he is a Warlock? That is, is a Warlock inherently aware where his power comes from? Or is it possible he believes the power comes from within, or just from studying?

If at all possible, how likely is it he would remain unaware as his powers grow, assuming he does have a base level knowledge about the magics in the world (D&D 5e), and does not have someone else telling him?

As you'd probably expect, this is left to both DM's and players' interpretation, but here are some general approaches to this:

• In a setting, where magic is common and frequently used by many people, it is quite plausible that the characters (both PC and NPC) would know and distinguish between different sorts of magic users, i.e. wizard's magic is not the same as the cleric's magic which is not the same as the warlock's magic. Would they call these people by their "classes"? Maybe not. But you might as well use those name since that's what they describe.




• If on the other hand the character is the only (or one of few) magic-users he ever met, he (and other NPCs) might not be aware of the distinction. But at that point, there is no value in him thinking his is a wizard rather than a warlock, because it might as well be the same (it's just a name for what he does after all).




• You can add flavour to your character by giving him this backstory of "he tried to be a wizard but became a warlock by accident and doesn't know it" in any case, since it doesn't affect anything mechanical as far as I can tell.

A Fighter who "swashbuckles" is a swashbuckler, but is not a Rogue Swashbuckler, who might actually be a fighter, but not a Fighter.

A male Wizard who styles themselves as a follower of wicca might call themselves a warlock but is not a Warlock, who might actually style themselves as a mage or wizard but are not a Wizard.

A Cleric with a tonsure and wearing a cassock is a monk, but is not a Monk.

etc.

You see what I am doing, class descriptions start with a capital, character descriptions have lowercase.

The point I am making is that there is a difference between game class and character's in character description. Though they may be the same, they also don't have to be and sometimes should not be. This is a different way of saying what has already been said in other answers, in my opinion, but emphasises the importance of role playing.

I have seen characters that quite reasonably don't know that they have class abilities let alone a class, they can just do things in character which are defined in the game by class abilities.

For instance there was a sorcerer that could just do magic, no training, no knowledge of the sorcerer class (they had a criminal background and, for want of another description, was a thief, just with no Rogue class levels) and as they progressed they got more powerful and was able to do more magic. This means they had no real idea they were a sorcerer, though of course they began to suspect when they picked up more "worldly knowledge".

It is down to how you want to role play a character whether they call themselves the same thing as their game class(es). It is true that the class names are designed to make it pretty easy to use them for exactly this reason, though how many times do you think some one will say anything like "I am a Rogue Seashbuckler/Ranger Gloom Stalker" as opposed to "I am a pirate of the Underdark seas!" for instance.

It's up to your DM (and you)

In this case: Your choice

As with everything in D&D the roleplay aspects are always free to be played with. If this is something the players and DM agree to (Or the DM decides on their own) then there is no reason it can't be that, it actually sounds fun and can open up some story elements down the line.

In General: Very

Your character should be aware of their class as far as knowing what it is they do and how, this might not extend to the rest of the world though.

"Warlocks" are a thing, they are clearly defined as a magic user who gains their magic from a pact with an otherworldly patron and therefore if your character has done this they know they're one, however they might present themselves as a wizard or Sorcerer if being a Warlock has any stigma in your world.

Other Classes also depend on what is socially acceptable.

A Cleric or Paladin would probably not hide the fact they are these classes, whereas a Rogue probably would.