I just had a random thought. Have you seen the star warlock from UA? I believe its official name was the Seeker. It has some abilities that can serve as good inspiration. Specifically I was thinking about the day-night cycle and time, and remembered they have an ability that allows them to gain a "fast short rest". This is obviously big for warlocks as they're short rest reliant. The TW is pretty short rest reliant as well, and manipulating the energies responsible for this time cycle fits the theme.