I'm guessing he meant to add this to the thread about the god of Plane of Time and Zeb and the rest of it.
The deity in control of the Plane of Tranquility is the child goddess, Quellious. Quellious doesn't have anything to do with New Taanan (aka Plane of Knowledge), however. There's some lame game reason why Quellious can't be found in PoTranquility (well, no there isn't -- the reason stated is "no one can find the goddess..." which is lame but isn't really a reason) but I assume the truth is that they didn't feel like modelling another deity in game if it wasn't going to get the crap kicked out of it and looted.
Wow. Regular ol' Joph fan club in here.