2d characters in 3d world can this be done?

what I'm asking about is not a "plain" 2d - like, everything being in 2d, nor 3d just constrained to 2d, because characters shouldn't be constained to 2 axis of movement only. what I'm asking about is something that we've seen in populous the beginning, for example alt text the world is 3d, and character can go anywhere, in 3d world, but their graphics are 2d.

How could this be done? or is there only a way of making a plane, putting a texture on it, and making it always "lookAt" the camera?

thanks in advance.

Correct, put a texture on a plane and have it always face the camera.