What would a good background choice be for a lizardfolk GOO chain warlock with Dendar the Night Serpent as a patron? My basic idea is that they gained the knowledge of how to form the pact after observing some Yuan-ti (or maybe torturing one), and now uses the powers granted for infiltration and remote magical combat (mask of many faces, one with shadows, and gaze of two minds amongst other options). Since the Actor feat is not an origin option, what would a good background option be? Or if I were to design a custom background, what origin feat would be beneficial? And as far as RP potential what would be the most fun?