[RPG] Is it okay to have a DMPC who is also the BBEG (Big Bad Evil Guy)

dnd-5egmpcvillain

I don't want to make my DMPC (i.e. Dungeon Master NPC) star of the show by any means, I realize how important it is to let the characters do their own thing. I want this character to act in the background and support the other characters from the side, not for party benefit, but because it benefits the DMPC character. The idea of having this subtly manipulative character influence the party for their own means and to quietly gain power from it intrigues me.

I want to have a grand twist where this character I've made betrays the party, and they realize that they've let themselves be led astray from their original task just a little bit too late for them to do anything about it. But by defeating the DMPC, they will also and up accomplishing their original goal.

For context, this campaign is set to take place in an off-shoot version of hell where many people are given free roam. So it would be kind of normal to have betrayal there.

I just want to know if it would be possible to pull this off.

Best Answer

You can have a NPC that is the BBEG.

There are a number of ways to have the ultimate enemy of your players accompany them at times during their adventures.

Multiple interactions is doable

The Curse of Strahd adventure opens with guidance about the players interacting with the boss multiple times (p. 10, under "When Strahd Attacks"):

Strahd isn’t a villain who remains out of sight until the final scene. Far from it — he travels as he desires to any place in his realm or his castle, and (from his perspective) the more often he encounters the characters, the better.

A DMPC is a contradiction in terms.

A dungeon master is not a player by definition. A PC is a player character. Any other character is a non-player character. A DMPC is just an NPC that the DM has some special attachment with. If anything, that attachment may be a liability for the story and fun of others at the table because it could be put above them.