Pluto is a pretty good pick for dark, as would Satan, but because of dark's futures, it's pretty hard to recommend heavy investment into dark without at least Anubis, so... maybe going with wind would be a better, safer option.
However, if you are thinking long term with wind, you should think about picking up Gaia or Aether instead of Titania. Once Azazel awakens, Cu AW, Az AW, Gaia AW, Aether will be your typical goto team for wind. Titania is pretty decent now to get your team up to speed, but falls off in usefulness (along with Cybele) after Az AW because everyone goes fast with her around. The choice between Gaia/Aether probably depends on your ability to AW Gaia. If you have the eyes to do it, Gaia will be super useful to help your team survive, if not, go with Aether, as an unawakened Gaia isn't that amazing.
Also, as mentioned by the previous poster, Tish pick for light is a good choice if your light grid is in good shape.